Tyre Glossary

    1. *
    2. 0 degree coverage
    3. 3D-BIS Technology
    4. 4 wheel drive
    5. 4D-Nano Design
    6. A, AO, AOE
    7. A/T (All Terrain)
    8. ABE: General operating licence
    9. Abrasions caused by braking
    10. ABS: Anti-lock braking system
    11. ACP(Adaptive Constant Pressure)
    12. Active CornerGrip Technology
    13. ActiveBraking Technology
    14. Ageing
    15. Air loss
    16. Air pressure
    17. Air pumping
    18. All year, all season, all weather tyres
    19. Aluminium rims
    20. AM8,AM9,AMP,AMS,AMX
    21. Anti theft lug nuts / bolts
    22. Aquaplaning
    23. Asymmetrical
    24. Axle position
    25. B, B1, BC, BL
    26. Balloon tyres
    27. Bar
    28. BDS-Lamellas, Bi-directional system
    29. Bead
    30. Belt displacement
    31. Belted tyres, steel belt tyres
    32. Bib-Mousse
    33. Bionics
    34. BioTRED
    35. Black Chilli Technology
    36. BLT: Raised Black Lettering
    37. BluEarth Technology
    38. Bolt cirle holes
    39. Braking distance
    40. BSL: Black Serrated Lettering
    41. BST: Black Serrated Lettering
    42. BSW: Black Sidewall
    43. C tyres
    44. Calender
    45. Camber
    46. Carcass
    47. Centrifugal force
    48. CH: Hydrocarbon
    49. Chassis
    50. Chassis geometry
    51. Clearance certificate
    52. CLIP ON, SIT, FIX, FLASH
    53. Coefficient of adhesion
    54. Coefficient of friction
    55. Commercial vehicle tyres
    56. Contact Area
    57. ContiSeal tyres
    58. ContiSilent tyres
    59. CORD
    60. Cord plies
    61. CP Tyres
    62. Cross aquaplaning
    63. DA Tyres: Downgraded tyres
    64. Diagonal tyres
    65. Differential gear
    66. Dimension indications on tyres
    67. Dimpled Sidewall Design
    68. Directional tyres
    69. Discontinued model, discontinued tyres
    70. DOT number
    71. Double marking
    72. Drainage
    73. Driveguard
    74. DSB: Diagonal Serrated Band
    75. DT1, G1
    76. Dueler
    77. E, A on Dunlop tyres
    78. Eagle
    79. EAN: European Article Number
    80. ECE 30
    81. ECE Test mark
    82. Eco-Impact
    83. Ecopia
    84. Emergency running properties
    85. ENWL: Extra Narrow White Lettering
    86. ETRTO: European Tyre and Rim Technical Organisation
    87. EU tyre label, European tyre labelling regulations
    88. European noise protection regulations
    89. F
    90. Fine balancing
    91. Flank
    92. Flank height
    93. Flexing
    94. Foam-in-Tyre Technology (FIT)
    95. Freedom of movement
    96. Friction
    97. Front+Rear Marking
    98. FSL: Flange shield
    99. Fuel consumption
    100. FuelSaving Technology
    101. G
    102. G/S: Golden Stripe
    103. Grip
    104. GRNX: Michelin Green X
    105. GW: Gold Wing
    106. H/D, HD
    107. H/T: Highway Terrain
    108. HelioCompound
    109. High speed capability
    110. High speed strength
    111. Homologation
    112. Hydrodynamic effect
    113. Imbalance
    114. IMS: Instant Mobility System
    115. Inch
    116. Inner liner
    117. Interact Technology
    118. Interlinking effect
    119. Intermediates
    120. Internal Sipe Locking Technology (ISLT)
    121. J, JRS
    122. K1, KA, K, K2, K3
    123. kPa: Kilopascal
    124. L
    125. Lamellas
    126. Lateral run-out
    127. LI: Load Index
    128. LK: Bolt circle diameter
    129. LLR: Low Rolling Resistance
    130. Low profile tyres
    131. Low resistance tyres
    132. LR
    133. LS
    134. LT: Light Truck
    135. M+S, M&S, M.S.: Mud and snow
    136. M/C
    137. M3
    138. Main groove
    139. Manufacturer tie-in
    140. Matching
    141. MC, MC1
    142. MGT
    143. Michelin Acoustic Technology (MAT)
    144. Mileage
    145. Minimum tread depth
    146. Mixed tyres
    147. MO, MO1
    148. MST
    149. MT, M/T
    150. Multi part rims
    151. N0, N1, N2, N3, N4, N5, N6, N7
    152. Nature-Based High-Performance Vegetable Oil
    153. NEO-T01
    154. NHS: Not For Highway Service
    155. No LBL: No Label
    156. Nokian Aramid Sidewall
    157. Non-Marking
    158. NT
    159. NW, NWW: Narrow White Wall
    160. NWS: Narrow White Stripe
    161. OBL: Outlined Black Lettering
    162. OE identical wheels
    163. OE: Original Equipment
    164. Off road tyres
    165. Off road tyres
    166. OGL: Outlined Golden Lettering
    167. Orange Oil Technology
    168. ORBL: Outlined Raised Black Lettering
    169. ORWL: Outline Raised White Lettering
    170. Over inflation
    171. Over-steer
    172. OWL: Outline White Lettering
    173. OWT: Outline White Lettering
    174. P: Passenger
    175. PAX-System
    176. Pirelli Color Edition
    177. PNCS
    178. POR Tyres
    179. POR-Tyres
    180. PR-code, Ply-Rating, Ply Rating
    181. Profile
    182. PSWW: Pinstripe Whitewall
    183. Racing tyres
    184. Radial tyres
    185. Radius, static
    186. RBB, RG, RL, RN, RU, RW
    187. RBL: Raised Black Lettering
    188. RBT: Raised Black Tubeless
    189. Red Letter: Red Lettering
    190. RED: Red Sidewall
    191. Refitting
    192. Regrooving
    193. Reinforced, reinf, RF, RFD, XL, EL
    194. Repairing damage to a tyre
    195. Replacement Tire Monitor (RTM)
    196. Replacing tyres
    197. Requirements profile
    198. Retreading
    199. Ridge N Flex
    200. Rim assessment certificate
    201. Rim base
    202. Rim classification
    203. Rim contour
    204. Rim diameter
    205. Rim flange
    206. Rim protection
    207. Rim shoulder
    208. Rim width
    209. Rims
    210. RL: Raised Letters
    211. RO1, RO2
    212. ROBL: Raised Outlined Black Lettering
    213. Rockproof
    214. Rolling circumference
    215. Rolling resistance
    216. ROWL: Raised Outline White Lettering
    217. RRBL: Recessed Raised Black Lettering
    218. RSB: Raised Serrated Band
    219. Rubber compounds
    220. Rubber types
    221. Run-out accuracy
    222. Runflat, RSC, RFT, SSR, DSST, ZP, RF, HRS, ROF, EMT, TD, MOE, MO Ext.
    223. Running surface
    224. RWL: Raised White Letter
    225. S identification
    226. S1
    227. Saw tooth
    228. SBL: Serrated Black Lettering
    229. Sealguard Puncture Protection
    230. Self Seal
    231. Self supporting tyres
    232. SET
    233. Shoulder abrasion
    234. Side wall
    235. SilentArmor Technology
    236. Silica compound
    237. Slick tyres
    238. Slip
    239. Slip angle
    240. Smart Seal Technology
    241. SmartTRED
    242. Snow chains
    243. Snowflake symbol, severe snow
    244. SnowProtect Technology
    245. SoundComfort Technology
    246. SOWL: Slanted Outlined White Lettering
    247. Spare wheel, replacement wheel, replacement tyre, emergency wheel, emergency tyres
    248. Special motorbike identification
    249. Speed index
    250. Spikes
    251. SRBL: Serrated Raised Black Lettering
    252. StabiliGrip
    253. Steering precision
    254. Stopping distance
    255. Storage
    256. Studless
    257. Summer tyres
    258. Suspension
    259. SUV: Sport Utility Vehicle
    260. SVSB: Slanted Vertical Serrated Band
    261. SW: Single White
    262. SWS: Slim White Stripe
    263. TCT: Trapezoid Contour Theory
    264. Temperature dependency
    265. Test certificate, tyre clearance, special tyres
    266. TL: Tubeless
    267. Toe out
    268. TOP Indicator Technology
    269. Torque
    270. TPMS: Tyre Pressure Monitoring System
    271. Tracking
    272. Traction
    273. Tread compound
    274. Tread, tread depth
    275. TT: Tube Type
    276. TWI: Tread Wear Indicator
    277. Twin tyres
    278. Tyre age
    279. Tyre checks
    280. Tyre classification, tyre size
    281. Tyre insurance
    282. Tyre manufacture
    283. Tyre purchase, fitting
    284. UHP: Ultra High Performance
    285. ULW: Ultra lightweight
    286. UMS: Ultra Mileage & Safety
    287. Under inflation
    288. Under-steer
    289. Uniformity
    290. URS (Ultra RunFlat System)
    291. UTQG: Uniform Tyre Quality Grading
    292. Valve
    293. Valve caps
    294. Vector
    295. Vmax
    296. VO
    297. VSB: Vertical Serrated Band
    298. VTS-Lamellas: Variable Thickness Sipe
    299. Vulcanisation
    300. Water penetration
    301. Wear and tear
    302. Wear indicators, abrasion indicators (TWI, DSI, WSI, VAI)
    303. Wear pattern
    304. WearControl Technology
    305. Weight specifications
    306. Wet weather performance
    307. Wheel balancing
    308. Wheel disc
    309. Wheel load
    310. Wheel sensors
    311. Wheel spacers
    312. Wheelbase
    313. Wide base tyres
    314. Winter tyres
    315. WL: White Letters
    316. WLT: White Letters
    317. WRL: White Raised Letters
    318. WS: White Stripe
    319. WSS: White Side Sign
    320. WSW: White Sidewall
    321. WW: White Wall
    322. WWW: Wide White Wall
    323. XC: Cross Country
    324. XNW: Extra Narrow White
    325. Y Lamellas
    326. Yellow and red dots on tyres
    327. Z Lamellas
    328. ZR - Tyres

      *

      This marking is found on the side wall of original tyres supplied with BMW and Mini models. These tyres have been developed and manufactured according to certain specifications and requirements of the car manufacturer. We recommend fitting four of the same tyres, so that the tyres can deliver optimal performance.
      Please note: Tyres with this marking can also be used with other vehicles.



      0 degree coverage

      0 degree coverage from Michelin stops wide base tyres losing their shape at high speed due to a variable fibre geometry in the nylon cord.



      3D-BIS Technology

      Revolutionary technology that ensures better grip on snow and ice, stability on wet and dry roads, more comfort than tiring drive. The 3D-BIS Technology(3D-Block Interlocking System) acts by locking all block elements together to improve and maintain the stability and tread stiffness, also allowing the number of sipes to increase for more grip on icy and snowy roads.



      4 wheel drive

      On a 4 wheel drive vehicle, all 4 wheels can move the car, in contrast to a front or rear wheel drive car. Some vehicles have permanent 4 wheel drive, others have selectable 4 wheel drive. Driving power can be spread differently over the front and rear axle.



      4D-Nano Design

      The Falken innovative technology with Cutting-Edge Simulation accelerates the development of new tyre materials which result in new high-performance tyres. The 4D-Nano Design combines "Research," "Prediction," "Production" and "Extraction" technologies which unlock the performance of the materials in the new high-performance tyre at a nano scale, thereby enabling engineers to utilize the full hidden potential of each material.



      A, AO, AOE

      This marking is found on the side wall of original tyres supplied with Audi models. These tyres have been developed and manufactured according to certain specifications and requirements of the car manufacturer.
      We recommend fitting four of the same tyres, so that the tyres can deliver optimal performance.
      Caution: Tyres marked AOE indicate emergency running properties, and may not be combined with other tyres marked A or AO, see Runflat.
      Please note: Tyres with this marking can also be used with other vehicles.



      A/T (All Terrain)

      Off road vehicles which are frequently used on rough terrain must be fitted with special off-road tyres. As the name suggest, all-terrain tyres get you through all kinds of surface, whether it’s mud, snowy forest tracks or a country road littered with potholes.
      Please note: These tyres come in both imperial and flotation dimensions.



      ABE: General operating licence

      An ABE or General Operating Licence (GOL) is required for registration of a production car and to allow it to drive on public roads. The official documentation for this General Operating Licence is the vehicle registration document or licence certificate. This document includes information about engine capacity, number of seats, code numbers, or towing capacity, and also any changes made to the vehicle with official TÜV approval (wide tyres, parts added to the bodywork and so on). If any changes were made to the vehicles and not noted in the vehicle registration document, this will cause the General Operating Licence to lapse and will be sanctioned accordingly. Caution: If unapproved wheels or tyres are used, then the entire vehicle licence certificate will lapse alongside the operating licence including insurance cover!
      Please note: In relation to alloy wheels “ABE” is commonly used to mean “approved for General Operating Licence”, which allows use of these wheels on special editions of the vehicle in question.



      Abrasions caused by braking

      Abrasions caused by braking can arise when brakes are fully applied (particularly without ABS). Here, the wheel locks completely and skids over the road. The profile on the contact area is eroded by the extreme heat and abrasion - which means the tyre is no longer round and must be replaced.



      ABS: Anti-lock braking system

      The anti-lock braking system (ABS) sometimes called the anti-lock limiter, stops the wheels locking up when the brakes are fully applied. This means the vehicle can still be steered properly. An electronic device controls the revolutions of all the wheels via wheel rev sensors, compares these with each other, and adapts their behaviour to the speed of travel. If the revs of one or all the wheels drop out of proportion to the others, the electronics pick up the risk of locking and immediately reduce the hydraulic pressure in the brake line of the wheel in question. Depending on the construction of the ABS, the hydraulic unit generally contains three or four channels to the individual brake cylinders. In dry, damp and wet conditions, the braking distance is generally shorter than for the same vehicle without ABS. On fresh snow or loose chippings, the braking distance with ABS may be slightly longer.
      Please note: In an emergency, press down hard on the brake pedal and do not be put off by any pulsing of the pedal.



      ACP(Adaptive Constant Pressure)

      The Falken High-Pressure Tread Design technology is a new concept that improves the footprint of the tyre, distributing the pressure evenly throughout the contact patch. With this technology the broader footprint enhances the grip and driving performance, increasing braking and direction stability performance, and ensuring that the tyre wear pattern is even.



      Active CornerGrip Technology

      Technology that enables driver to easy maneuver tight turns. This is being done by outside tread grip increase while inner tyre grip decreases dramatically. A layer of a high strength material that features added durability and toughness, named Armid helps to improve the pressure distribution on the contact patch, providing more grip.



      ActiveBraking Technology

      Innovative 3-dimensional block design that increases the contact area during brake. Advantage of this technology is a shorter braking distance on dry and wet roads.



      Ageing

      A variety of factors can influence the ageing process of a tyre: Humidity, UV radiation, heat, cold etc.
      In order to avoid a reduction in performance, other substances are mixed with the rubber compound to significantly slow down the ageing process. However, you should replace your old tyres with new ones after ten years at the latest. It is a natural process for rubber to age, during which its elasticity and grip can change. This is a very slow process, and can be delayed further by special anti-ageing materials in tyres. However, a pristine spare tyre which has been lying in your boot for over 6 years, should not be used together with completely new tyres.



      Air loss

      The words ”Air Loss” immediately make you think of a sudden, obvious or gradual loss of air, such as that caused by a puncture.
      However, air pressure goes down continually even without any outside influence, as the inner liner of a tyre can never be sealed 100%. The following rule of thumb applies: Check your tyre pressure every other time you refuel. This is also possible when the tyres are filled with a special gas (e.g. nitrogen). However the special effect of the gas gradually disappears as you top up with normal air.



      Air pressure

      The correct air pressure is critically important for the mileage and life span of the tyres, as well as driving safety. If tyre pressure in the tyres is tool low, it can lead to poor weight distribution and overheating, or even to the risk that the tyre may blow out. In addition, rolling resistance is increased, leading to an increase in fuel consumption. Regular studies have shown that approximately only one in four cars on the road has the correct air pressure. You will find the air pressure recommended by the manufacturer in the vehicle’s instruction manual, and also on the fuel fill flap or on the side of the door. Air pressure should be checked at every other stop at a service station, or at least every four weeks. Tyres must be checked when cold, as warm tyres have a higher pressure. Therefore: never release air from a warm tyre! Under certain circumstances, wide tyres require different air pressure to standard tyres, in this case please make sure to consider the information in the user manual or from the tyre manufacturer.



      Air pumping

      Air pumping is the specialist term used for air pumping out of tyres when the tyre is rolling. The weight of the vehicle presses the tyre onto the road with great force, so that air flows at great speed our of the tread channels when the tyres rotate. At high speed, whistling and hissing sounds can occur, which can however be reduced by skilled variations tread design.



      All year, all season, all weather tyres

      In the car area, so called all-weather or all year tyres are available as well as summer and winter tyres. All weather tyres must be marked with the symbol “M+S”, just like winter tyres. Manufacturer names such as “Allweather” or “All season” signify what is also meant by special symbols on the side of the tyre: Snowflake, leaf, sun and raindrop symbolise the different types of weather conditions which the all weather tyres are suitable for.
      Naturally these tyres represent a compromise - they don’t reach the high standard of driving properties of summer tyres in warm weather and dry conditions or those of winter tyres in the cold and snow. All weather tyres are an option for motorists who live in a relatively flat area, and can occasionally leave their car at home in extreme weather conditions.
      Please note: If an all weather tyre is not available in a certain size, a winter tyre can be used in its place.



      Aluminium rims

      Aluminium rims are rims which are made from aluminium alloy - not from pure aluminium. Pure aluminium is too soft to guarantee the strength required and meet the challenges of driving on the road.
      In contrast to steel rims, alloy wheels are available in almost any size or width. So you can only get 22, 23 or 24 inch rims as alloy wheels.
      Alloy wheels add value to any car due to their design. Many are more suitable for summer, as they more sensitive to road salt than steel wheels due to their finish. However, special winter alloys with a winter resistant coating are available.



      AM8,AM9,AMP,AMS,AMX

      These abbreviations stand for Aston Martin specifications. These tyres have been developed and manufactured according to certain specifications and requirements of the car manufacturer. We recommend fitting four of the same tyres, so that the tyres can deliver optimal performance.
      We recommend fitting four of the same tyres, so that the tyres can deliver optimal performance.
      Please note: Tyres with this marking can also be used with other vehicles.



      Anti theft lug nuts / bolts

      An anti theft lug nut or bolt is a wheel nut or bolt which protects the wheel from theft. It can only be unscrewed with a special key.



      Aquaplaning

      Aquaplaning occurs when the grooves in the tyre can no longer lead the water under the tyre contact area to the outside. The tyres then float on the film of water, so braking power and steering power are no longer applied to the driving surface.
      Aquaplaning can be recognised by light steering, spinning drive wheels with high engine revs, and the sound of water under the car. Anyone who finds themselves unexpectedly aquaplaning should not try to brake under any circumstances, but should instead depress the clutch and keep the steering wheel in the direction of travel. The wheels must not lock, or be pointing in the wrong direction when they come into contact with the road again. Drivers of automatics should concentrate on their steering and not attempt to change the driving mode. The following applies in the rain: Drive carefully!



      Asymmetrical

      Asymmetrical tyres have an inner and an outer side. This is indicated by the words “Inside”/”SFI” and “Outside”/”SFO” on the side walls.
      After fitting, the wheels can be used in any position on the vehicle, in contrast to directional tyres. However, the side initially chosen to be the axle side should be kept with subsequent changes of wheel, as tyres always wear slightly unevenly due to direction and vehicle set up, and so adapt perfectly to the road.
      The profile of asymmetric tyres is designed differently on the inner and outer shoulders: Whereas the profile on the inner shoulder provides traction and straight running, the profile on the outer shoulder is designed for optimal steering and stability when cornering.



      Axle position

      When changing a wheel, you should bear in mind the axle position, as this indicates what position a wheel was fitted in, or should be fitted in. Regardless of the type of drive, forces affect each wheel differently. As a rule of thumb you can say that tyres with deeper tread belong on the rear axle.
      So the position of the wheels may be changed to use them evenly, e.g from FL to RL or FR to RR. The axle side initially chosen should stay the same, as the tyres adapt to the axle geometry. This guarantees the optimum contact area. Directional tyres must always be kept on the original axle side.



      B, B1, BC, BL

      These abbreviations stand for Bentley specifications. These tyres have been developed according to certain requirements of the car manufacturer. They are specially aligned to the manufacturer’s chassis and from part of the vehicle’s original equipment.

      We recommend fitting four of the same tyres, so that the tyres can deliver optimal performance.
      Please note: Tyres with this marking can also be used with other vehicles.



      Balloon tyres

      With balloon tyres, the ratio of height to width is 0.98 :1. They offer good suspension, but poor cornering properties.
      Balloon tyres are no longer common on modern cars. They are only used with vintage cars and as specialist tyres.



      Bar

      Bar is the legal unit of measurement for pressure. This is the unit of measure commonly used for tyre pressure and replaces the unit “physical atmosphere” (atm).
      One mbar corresponds to 100 Pascal.



      BDS-Lamellas, Bi-directional system

      Michelin’s bi-directional system (BDS) is a special lamella system where the lamellas go in two different directions. Because of their arrangement they are also called “Z-Lamellas”. These lamellas block each other when braking and accelerating, leading to better handling.
      BDS-Lamellas are used on the Michelin Alpin and Pilot Alpin winter tyres amongst others.



      Bead

      The bead or inner ring on the side of the tyre contains strong wire cores and has the task of ensuring the tyre sits securely on the rim.



      Belt displacement

      In a tyre where the pressure it too low, the increase in flexing can give rise to temperatures up to 120° C. Particularly in the shoulder area, this can lead to overheating of materials, causing parts of the running surface to displace.



      Belted tyres, steel belt tyres

      In belted tyres, the fabric is reinforced with metal wires and textile bands which go round the tyre like a belt. In belted tyres, the fabric is perpendicular to the direction of travel. The belt, which goes over the fabric in line with the direction of travel gives the belted tyre similar side wall strength to a diagonal tyre, but they are generally more flexible and thus less liable to slip on wet roads.
      The big advantage of belted tyres in their more stable running surface, giving them better road-holding. A car with belted tyres will corner better, has better braking distances, drives more safely on wet roads - and the tyres also last longer, but all at the cost of comfort.
      Caution: Steel belts can rust. This means any tyre with deep damage to the surface such that moisture (even air humidity) could get to the steel wire must be taken out of circulation immediately.



      Bib-Mousse

      Bib Mousse is a foam rubber ring which acts as puncture preventing replacement for inner tubes on motorbike tyres. A new Bib Mousse ring is equivalent to a reinforced tube with 0.9 bar pressure.
      Caution: The Michelin Bib Mouse is not authorised for use on the road, and may only be fitted in Michelin tyres!



      Bionics

      The science of bionics is concerned with how we can learn from nature, and how we can transfer what we have learned to technology and new developments,
      So for example, we can minimise the air resistance of tyres with a surface similar to sharkskin.



      BioTRED

      BioTred is the name given to a tread compound from Goodyear, which contains a corn starch component. This makes it possible to produce tyres in an environmentally friendly way. It also reduces rolling resistance, saving fuel and money.
      BioTred 2 is based on a palm oil derivative, which is used instead of crude oil derivatives such as carbon black.



      Black Chilli Technology

      Black Chilli” is a special rubber composition from Continental with racing carbon blacks, resin and nanoparticles. It improves the versatility of the tread on the roadway and increases the stability and traction of the tyre. When braking, the powerful vibrations of the tyre are converted into heat through short-chain polymers in the tread, which enables better grip on the road and shorter braking distances. At constant speed, the vibrations are smaller, and long-chain polymers ensure that the energy is dissipated outwards. The tyres remain cooler, and the lower roll resistance increases the mileage.



      BLT: Raised Black Lettering

      Special design of side wall lettering, slightly raised black letters.



      BluEarth Technology

      BluEarth is a technology that delivers driving pleasure, protects the environment and is socially friendly. BluEarth technology can be found in all Yokohama BluEarth pattern series. This technology adds the value to the tyres by Fuel Saving and Environmental Friendly.



      Bolt cirle holes

      The number of holes indicates the number of wheel bolts or nuts used to attach a rim to the vehicle. Often 4-5 wheel bolts or nuts are used, however a minimum of 3 - on lorries there may also be more.



      Braking distance

      The distance between pressing the brake and the vehicle coming to a complete stop is known as the braking distance. Several factors influence the braking distance: Driver reaction time and length of braking, brake system reaction time, road conditions (type, wet), weight of the vehicle, condition of the tyres (manufacture, depth of profile, pressure) and speed.



      BSL: Black Serrated Lettering

      Special design of side wall lettering, serrated letters.



      BST: Black Serrated Lettering

      Special design of side wall lettering. The lettering is serrated inside the edge.



      BSW: Black Sidewall

      Special design of the side wall. Tyres with a black side wall.



      C tyres

      Reinforced tyres for light lorries, vans and good vehicles are known as C tyres. Depending on the manufacturer, the “C” stands for “Commercial” or “Cargo” but they both relate to the same thing. On many C tyres there is a double marking for the maximum load for single or twin tyre formations.
      Originally, the abbreviation “PR” was located on the side wall of tyres for good vehicles. This refers to the Ply Rating, which formerly indicated the number of body ply cords, thus representing the load bearing capacity. which is nowadays shown by the load index for vans or goods vehicles. So tyres with 8PR rating had a higher load-bearing capacity than 6PR tyres.
      When selecting tyres for a goods vehicle, the primary considerations are construction type and load index.
      Caution: RF-/XL tyres and LT tyre are not C tyres, even if they resemble them with regard to size and load index. Therefore you should check the paperwork for your vehicle or ask the manufacturer which tyres you can use.
      In contrast, the abbreviation “CP” stands for “Camping”. This refers to C tyres which are optimised for the particular requirements of mobile homes, such as long standing times.
      In contrast, the abbreviation “CP” stands for “Camping”. This refers to C tyres which are optimised for the particular requirements of mobile homes, such as long standing times.



      Calender

      Calender is an expression used in the manufacture of tyres. It refers to a beading system where the cord fibres are coated thinly on both sides with rubber.



      Camber

      The inclination (angling) of wheels towards each other, when viewed in the direction of travel, is known as camber. It is shown as the angle of the plane of the wheel to the vertical plane with respect to the ground. If the inclination towards the top points outwards, the camber is positive. This suppresses the tendency to flutter. If the wheels point inwards at the top, the camber is negative, leading to increased lateral control.



      Carcass

      This essential element of the load bearing sub-structure of the tyre gives the tyre its strength and ensures it stays together. Nowadays, carcasses consist of a plastic and cotton fibre fabric or steel cord, embedded in the rubber.



      Centrifugal force

      Centrifugal force is the force which pushes the vehicle outwards when cornering. The greater the weight of the car and the speed, the greater the centrifugal force.



      CH: Hydrocarbon

      Hydrocarbons (CH) are present in emissions in many variations. There is a corresponding variety of odours (aromatic to pungent). There is also a similar range of effects on human health. Some CH compounds have a narcotic effect, at least in high concentrations, and others irritate the mucous membrane, or are more or less poisonous. Certain, so called aromatic CH compounds such as benzene are categorised as carcinogenic. At normal atmospheric concentrations, CH compounds are of particular relevance in relation to the formation of smog, whose main constituent is ozone.



      Chassis

      The chassis includes the following elements:
      Wheel suspension (axles).
      Suspension.
      Shock absorbers.
      Steering.
      Brakes.
      Wheels (rims and tyres).
      The chassis creates a connection between the bodywork and the road, and its character is responsible for both the comfort of the vehicle and its road holding performance. Can manufacturers are constantly trying to find the balance between safe road-holding and corresponding comfort of the vehicle.
      The problem is that one does not actually exclude the other, but they do significantly influence each other. On the one hand, a stiff chassis gives a high level of driving safety, (good traction, directional stability, road holding, speed of reaction), albeit always at the expense of comfort.



      Chassis geometry

      Chassis geometry includes camber, tracking, and caster, and depending on the vehicle also rake. Changing or adjusting the chassis geometry can often have a detrimental effect, for example changes to steering force or impaired straight line running.



      Clearance certificate

      Tyre sizes and rims which are not entered in the vehicle’s documentation many only be used after a clearance certificate has been issued. This will be issued by the vehicle manufacturer or tyre manufacturer, or another expert, thus allowing the tyres ad rims to be fitted.



      CLIP ON, SIT, FIX, FLASH

      CLIP ON, FIX and FLASH are all tyre references for rim bases which are side-split or Lemmerz contoured without closing rings, side rings or cross shoulder rings. SIT makes fitting easier: Continental were the first to bring out the first major innovation from the forklift area in the shape of the Snap In Tyre, which represented significant time savings across the board. The patented SIT construction comes without any loose rim parts. This results in optimal positioning of the rim, cost savings due to the lack of loose parts, plus easy and fast fitting.



      Coefficient of adhesion

      The coefficient of adhesion indicates the roughness of various pairings of materials between the underside (e.g of tyres) and substrate (e.g. road). It is indicated by the Greek letter µ.
      Low values indicate a smooth, slippery, low friction pair of materials. With higher values there is a greater frictional force to overcome.



      Coefficient of friction

      The coefficient of friction of a tyre is not constant, rather it varies depending on temperature, surface pressure in the contact area, slip and numerous other factors.



      Commercial vehicle tyres

      Commercial vehicle tyres are tyres which have been specially developed for vans, lorries and buses. The main priorities are economy and a long life span.



      Contact Area

      The area of the tyre which actually touches the surface is known as the contact area. With a car, this is roughly the size of a postcard.



      ContiSeal tyres

      Tyres in the ContiSeal range are different in that they have a viscous, sticky coating - between the shoulders on the inside of the tyre.
      If a foreign object penetrates a ContiSeal tyre, the viscous coating surrounds it and prevents any loss of air. If the foreign object falls out, the hole is sealed off by the sticky, viscous coating.
      You don’t have to interrupt your journey to change the wheel, you can just go on to the nearest tyre specialist.
      Please note: ContiSeal technology only seals off holes up to 5 mm.
      Caution: The viscous coating is not suitable as a permanent repair after a puncture. After any damage to a tyre you should consult a tyre specialist, who will check if the tyre can be repaired.
      A tyre pressure monitoring system in the vehicle is required when using ContiSeal tyres.



      ContiSilent tyres

      ContiSilent technology lowers perceived road noise from the tyres for car occupants. Here the tyres are equipped with a foam on the inside, which keeps its shape even when temperatures change dramatically, thus minimising generation of noise.
      Road noise inside the vehicle can be reduced by up to 9 dB (depending on the type of driving, speed and road surface).



      CORD

      These tyres have been developed and manufactured according to certain specifications and requirements for Daimler-Chrysler.

      We recommend fitting four of the same tyres, so that the tyres can deliver optimal performance.
      Please note: The tyres can also be used on other vehicles.



      Cord plies

      Cord plies are threads made of rayon, nylon or polyester. They are woven and incorporated into the rubber of the tyre adding considerable strength. Running these cords from bead to bead determines the type of tyre construction, which can be diagonal or radial tyres.



      CP Tyres

      CP tyres have been developed for camping vehicles such as mobile homes and are fitted with a reinforced sub structure. Equivalent to C tyres in terms of construction, CP tyres therefore have a high load bearing capacity. Due to considerably higher air pressure, CP tyres have higher load bearing capacity and at the same time, greater protection from mechanical damage. This reinforcement is done over several layers as in 205/55 R16 99 CP V tyres. This protects the tyres during a long stationary period on a base plate.
      Caution: RF-/XL tyres and LT tyre are not C tyres, even if they resemble them with regard to size and load index. Therefore you should check the paperwork for your vehicle or ask the manufacturer which tyres you can use.
      In contrast, the abbreviation “CP” stands for “Camping”. This refers to C tyres which are optimised for the particular requirements of mobile homes, such as long standing times.



      Cross aquaplaning

      Cross aquaplaning can occur when cornering on a wet road surface. In this dangerous situation, the vehicle suddenly loses contact with the road. The lateral centrifugal force is so powerful that the vehicle eventually skids out sideways.



      DA Tyres: Downgraded tyres

      DA tyres are tyres which have some visual faults and are correspondingly ”downgraded” by the manufacturer. So they may be marked with a stamp for example.
      These visual faults have absolutely no effect whatsoever on performance or properties.



      Diagonal tyres

      In diagonal ply tyres, the cords run at an angle to the direction of travel. This means the side wall of the tyre is more stable than in radial tyres. However, this leads to a smaller contact area, as well as a reduction in stability when cornering. Whereas diagonal tyres are still used today with motorbikes, agricultural and industrial equipment, they have been almost completely replaced by radial tyres for cars and commercial vehicles.
      Depending on the design they can be used with an inner tube (TT) or without an inner tube (TL).



      Differential gear

      Differential gears or differentials equalise the differing revolution rates of the wheels on the drive axes.
      Differing rates of revolution of wheels inevitably occur as the wheels on one axle have to cover different distances when cornering. Here the wheel on the outside of the bend always goes more quickly than the wheel on the inside. In most cases, a so-called bevel gear differential equalises the revolutions on the drive axle. Where built in, a limited slip differential prevents the wheels from spinning freely and directs the power to the wheel with the better level of traction.



      Dimension indications on tyres

      The dimensions shown on the side wall of a tyre indicate type of construction, size, maximum speed and load capacity. In general a vehicle must only be fitted with tyres as indicated in the vehicle licencing documents (or registration certificate part 1). As the registration certificate part 1 (since October 2005) only shows tyre size, the alternative tyre options should be taken from the CoC (Certification of Conformity). There are, however, a number of exceptions in this regulation. So there are a number of cars (mainly old ones) where 82 series tyres are specified. As these are virtually identical in size to 80 series tyres, both types may be used, according to a statement form the Federal Ministry of Transport. No change or addition to the vehicle documentation is needed, as long as speed and load index is the same or higher than indicated in the paperwork. This allowance is also valid in the opposite direction – 82 series tyres may also be used instead of 80’s. This was determined by the Federal Ministry of Transport in 1990 in §36 of the StVZO (German Road Traffic Regulations) Appendix 9.



      Dimpled Sidewall Design

      Falken Technology that boosts the durability of the tyre. Dimples on the sidewall increase the efficiency and heat dissipation in run-flat mode, reducing the thickness at specific points, thereby increasing the surface area and boosting the air circulation. It is the ideal combination of modern designs and tyre functionality.



      Directional tyres

      Directional tyres should only be fitted to the car in the direction of travel intended. This direction of travel is identified by an arrow and the word “rotation” on the side wall.
      After fitting on the rims this gives two “left” and two “right tyres. Directional tyres often have a tread which looks like a “V”. This type of tread pattern has the following advantages:

      • lower level of road noise
      • better traction in the wet
      • greater aquaplaning safety



      Discontinued model, discontinued tyres

      Discontinued lines may have an older DOT number (date of manufacture) and are often no longer in production.



      DOT number

      The abbreviation DOT stands for the US Department of Transportation and in many countries, it is valid and the legally required approval in the tyre industry. DOT means that the tyre meets or even exceeds the safety requirements of the Department of transportation.
      1. The tyre meets or exceeds the safety requirements of the Department of Transportation.
      2. Place of manufacture and plant code (assigned by the DOT).
      3. Size code.
      4. Optional manufacturer’s code to identify the brand and tyre properties.
      5. Date of manufacture.
      There are a number of indicators relating to tyre construction which are located on the side wall in the form of numeric codes. Generally, however, this refers to the tyre’s date of manufacture. The age of the tyre is indicated, encrypted. So, for example, “327” could mean week 32 of 1997. As of 2000, the week and month of manufacture of a tyre have been show as four digits. So the last four digits show the week and year in which the tyre was made, for example “1602” means week 16 of the year 2002.



      Double marking

      On light trucks or van tyres, also known as C tyres, there are often two figures for the load index shown on the side of the tyre, for example 205/55 R16 C 98/96H.
      These two numbers indicate the load capacity for single tyres (98) and twin tyres (96). In this case the maximum load capacity of a tyre would be 750 kg for a single tyre, or 710 kg for twin tyres (with tyre pressure of 2.5 bar). The lower load index in the two numbers always stands for the maximum load capacity for twin tyres.



      Drainage

      Drainage refers to the deflection of water by the tread. Tyres must have good drainage performance in order to guarantee safe driving performance in wet conditions. Using computer simulation, the water deflection speed of a certain tread can be calculated, and the tyres ability to combat aquaplaning optimised with linear or lateral drainage.



      Driveguard

      DriveGuard - It's a tyre with a reinforced sidewall from Bridgestone tire manufacturer. Additionally, the tyre has a special design that keeps the friction as low as possible with a defect and thus restrains the heat. The tyres, which are made with this technology, you can drive up to 50 miles distance up to 50 mph even if the pressure would be lost (eg, due to the nail.)



      DSB: Diagonal Serrated Band

      Special design of side wall lettering. The lettering is serrated inside the edge.



      DT1, G1

      These tyre markings are part of a Michelin specification and signify that the tyres should be fitted per axle. Tyres with different markings should not be combined with each other.



      Dueler

      Dueler is the Bridgestone umbrella term for all offroad-profiles



      E, A on Dunlop tyres

      The letter “E” on Dunlop tyres stands for tyres which have been enhanced to minimise rolling resistance, fitted as original equipment to some cars. An A stands for a special Mercedes design.



      Eagle

      A successful Goodyear product range of high-performance sports tyres.



      EAN: European Article Number

      The European Article Number (EAN) gives every tyre model a unique article number.



      ECE 30

      ECE 30 refers to a European guideline which is documented on the tyre by the E number. The E number is specific to every tyre design and confirms that the tyre in question has met the test criteria specified in ECE 30. In Germany, since 1998, only tyres produced after this date which meet the test criteria can be sold. Amongst other things, the ECE 30 protects the consumer from serious safety faults which can arise from cheap imports, for example.



      ECE Test mark

      Point 4 (Tyre classification) of §36 StVZO (German Road Traffic Regulations) states the following:
      Tyres on vehicles with a top speed of over 40 km/h must be furnished with information such as tyre size, type of construction, load capacity, speed category and date of manufacture (or re-treading date). In addition, since 1998, the ECE identification must be included.



      Eco-Impact

      Eco-impact is a manufacturer term for energy saving tyres from the brand Pirelli. These tyres are designed for environmentally friendly performance (classed as “Green Performance” by Pirelli).



      Ecopia

      Ecopia tyres from Bridgestone combine low rolling resistance with outstanding safety and performance in wet weather.



      Emergency running properties

      seeRun-Flat



      ENWL: Extra Narrow White Lettering

      Abbreviation on the side wall of a tyre. These tyres have narrow white letters.



      ETRTO: European Tyre and Rim Technical Organisation

      The European Tyre and Rim Technical Organisation (ETRTO) has the following regulatory objectives:
      - Promotion of a standardisation of norms, in order to achieve transparency with regard to fitting and use of tyres, rims and valves in Europe
      - establishment of common guidelines for measurement, load and pressure regulations and usage
      - Promotion of unimpeded exchange of technical information regarding tyres, rims and valves.
      In view of the fact that tyres make a considerable contribution to road safety, the ETRTO works with national and international organisations and legislative bodies in order to make suitable recommendations.



      EU tyre label, European tyre labelling regulations

      Since the 1st of November 2012, the EU tyre label has rated tyres with respect to fuel efficiency, braking on wet surfaces and external road noise.This means the consumer can find out about these features before buying a tyre.The label does not provide other key data such as driving stability, wear and tear or braking on dry roads.



      European noise protection regulations

      When a tyre is provided with a noise protection approval number, it meets the requirements of regulation 2001/43/EG, and the new noise limits which apply in European countries.



      F

      The identifier “F” can stand for Ford or Ferrari specification. These tyres have been developed and manufactured according to certain specifications and requirements of the car manufacturer.
      We recommend fitting four of the same tyres, so that the tyres can deliver optimal performance.
      Please note: The tyres can also be used on other vehicles.



      Fine balancing

      In fine balancing, the wheels are balanced directly on the vehicle. Any remaining imbalances arising from changes to wheel centring, hubs and brake discs are dealt with.



      Flank

      Flank is a synonym for the side wall of the tyre. It effects the driving characteristics and comfort.



      Flank height

      Flank height is in proportion to the tyre width. For tyre size 175/70R13 the 70 indicates the as a percentage based on the tyre width of 175 mm.



      Flexing

      Flexing is the periodic compression of the tyre. It distorts the side wall and the shoulder, releasing heat and creating additional rolling resistance. If tyre pressure is too low, the tyre flexes more and the tyre overheats.



      Foam-in-Tyre Technology (FIT)

      The foam-in-tyre technology developed by Dunlop uses a foam ring inside the tyre. This reduces road noise significantly, without negatively affecting mileage, rolling resistance or high speed stability.



      Freedom of movement

      The freedom of movement of the wheel must be guaranteed at all times. This means that tyres and wheels must never be allowed to touch the chassis or components such as brakes or the steering tie rod.
      When re-fitting with a larger wheel / tyre combination, it may be necessary to extend the wheel arches.



      Friction

      When a vehicle moves and stops, it causes friction between the tyres and the road. The tyre surface is worn off during this, and there is a residue, this is visible on the road as a skid mark for example.
      The following factors effect the level of friction: Road surface characteristics, driving speed, distribution of weight, tyre pressure, temperature and tyre properties.



      Front+Rear Marking

      Front + rear marked tyres are tyres which can be fitted to the front or rear rims according to the manufacturer.



      FSL: Flange shield

      The flange shield is a rubber bead on the outer edge of the tyre. This flange is intended to stop the rim getting scratched on the kerb while parking for example,
      The following codes are also used by tyre manufacturers:

      • MFS: With rim protector
      • MFSL: With flange shield
      • RPB: Rim protection bar
      • FP: Fringe protector
      • FR: Tyre rib



      Fuel consumption

      Essentially, car buyers judge the efficiency of a vehicle according to the fuel consumption data, This figure is determined by a variety of factors. These include the weight of the vehicle, efficiency of the engine, the front surface of the vehicle,driving speed, engine speed and accelerator settings. Fuel consumption isn’t just an interesting subject in terms of economics, but also from an ecological viewpoint. The technical competence and the development efforts of a manufacturer are reflected in the level of fuel consumption of their vehicles. Car manufacturers have to give three sets of figures for fuel consumption: urban, extra-urban and combined, whereby 36.8% of consumption is urban and 63.2% is extra-urban. Testing starts with the basic urban cycle and a cold start at 20-30° C. After measurement of emissions and consumption under the same conditions, the fuel consumption is calculated on the basis of exhaust emissions, including CO2.



      FuelSaving Technology

      Lightweight carcass combined with an advanced polymer resulting less use of energy when unwinding, lower costs of fuel and CO2 emissions.



      G

      Tyres marked with a “G” have been specially developed in cooperation with the car manufacturer Opel. These tyres have been developed and manufactured according to certain specifications and requirements of the car manufacturer.
      We recommend fitting four of the same tyres, so that the tyres can deliver optimal performance.
      Please note: The tyres can also be used on other vehicles.



      G/S: Golden Stripe

      Special design of the side wall. Tyres with a gold stripe on the side wall.



      Grip

      The expression “Grip” describes the friction between the contact surface of the tyre and the surface under the tyre.
      So the grip is the ability of the tread rubber compound to stick to the road as firmly as possible, whereby experts differentiate between the macro and micro roughness of the road surface. Grip in the wet and especially on snow is achieved via sophisticated lamella technology and special rubber compounds.



      GRNX: Michelin Green X

      Michelin’s own term for energy saving tyres.



      GW: Gold Wing

      Tyres specially developed for Honda Gold Wing motorbikes.



      H/D, HD

      Tyres specially manufactured for Harley-Davidson.



      H/T: Highway Terrain

      Highway Terrain (H/T) tyres were developed to give the driver the best possible conditions on both wet and dry road surfaces. They are characterised by excellent comfort, low road noise and optimal driving properties.
      What makes HT tyres special is they can also be used well off-road to a certain extent. Performance has been optimised for roughly 20% off-road and 80% on-road. These tyres are a good option for anyone who takes their SUV into the woods now and again, or occasionally goes off-road.



      HelioCompound

      HelioCompound is a rubber compound for winter tyres patented by Michelin. In addition to silica, as special protection it contains sunflower oil, which enables the material to remain supple and flexible at low temperatures. The goal of the HelioCompound technology is to improve the tyre grip and to shorten the braking distance even in conditions with moisture, snow or ice.



      High speed capability

      In order to determine high speed capability, a tyre must maintain its maximum speed (speed index) for an hour on a roller dynamometer. In the next test, the speed is increased by 10 km/h every ten minutes, to test when the tyre fails.



      High speed strength

      At high speeds, there is an enormous centrifugal force affecting the tyre. In order to withstand this, the carcass is firmly bound together by nylon fabric.



      Homologation

      Homologation refers to the technical authorisation of a tyre for a certain car model of car. The whole authorisation process is very strictly controlled by the car manufacturers, and around 60 individual checks come into consideration. Every authorisation signifies a confirmation of quality for the tyre manufacturer. In Germany, where the manufacturers are particularly demanding, Michelin are authorised for all manufacturers for almost every profile.



      Hydrodynamic effect

      Hydrodynamic effect refers to the accelerated flow of water created by arrow shaped treads arranged in the direction of travel.



      Imbalance

      Even very minor irregularities in the thickness of material or other issues such as uneven wear can cause tiny imbalances in the tyre. When the wheels revolve, these create an imbalance, and the tyre no longer spins evenly. In most cases, this can be equalised by a counter weight on the rim.



      IMS: Instant Mobility System

      The Instant Mobility System (IMS) was developed by the manufacturer Dunlop. IMS is a puncture kit which consists of a container with a sealant and a compressor. Vehicles with IMS do not need a spare wheel, saving fuel due to the reduction in weight.
      So minor damage to tyres can be fixed by the driver, and small punctures can be sealed. After any damage to a tyre, it should always be checked out by an expert.



      Inch

      Inch is a unit of length (“) which is used particularly in the English speaking world. For example, inches are used for the diameter of rims.
      For conversion to metric:
      1 inch = 25.4 millimetres
      1 millimetre = 0,03937 inches



      Inner liner

      The inner liner is the name given to the rubber layer which ensure air tightness on the inside of the tyre. In tubeless tyres, it fulfils the role of an inner tube.



      Interact Technology

      Interact Technology delivers high performance in all road conditions. The Multi-Zone Tension Technology in Interact tread patterns offers adaptive mileage, grip, and handling on every type of road.



      Interlinking effect

      So that winter tyres can really “bite” into snow, they have edges and grooves like lamellas, which compress the snow into a “tooth rail”. This gives rise to an interlinking of tyre and road surface.



      Intermediates

      Intermediates is a motor sport classification for racing tyres with a tread cut on the spot by hand, which provide the best compromise on damp or drying road surfaces.



      Internal Sipe Locking Technology (ISLT)

      Internal Sipe Locking Technology (ISLT) is a technology from Vredestein for improving tread stability in tyres with lamellae. Through tread structure in the spaces between the lamellae, the lamellae bite into each other when under strain and give each other support. The minimisation of the lamela distortion sabilises the tread bars and thus the tread. Through lamellae, ISLT combines the benefit of good road grip with better handling and higher steering precision.



      J, JRS

      Tyres with this abbreviation have been developed and manufactured according to certain specifications and requirements of the car manufacturer Jaguar.
      We recommend fitting four of the same tyres, so that the tyres can deliver optimal performance.
      Please note: The tyres can also be used on other vehicles.



      K1, KA, K, K2, K3

      With Michelin tires, K1, K2, and K3 represent Ferrari and Maserati specifications – these tyres are developed and produced according to certain specifications and requirements of the vehicle manufacturers. K1 and K2 feature new rubber compounds and modern tread patterns; these should not be mounted together with older tread patterns.
      Note: These tires can also be employed on other vehicles.

      With Pirelli tires, the abbreviations stand for:

      Technical designation  K1:  Designation for various tread pattern

      Technical designation  K2:  Designation for various tread pattern

      Technical designation  KA:  Designation for various dimension/size



      kPa: Kilopascal

      kPa (Kilopascal) is a unit of measure for air pressure. 1 kPa = 0,01 bar 1 bar = 100 kPa



      L

      Tyres with this designation have been developed and manufactured according to certain specifications and requirements of the car manufacturer Lamborghini.
      We recommend fitting four of the same tyres, so that the tyres can deliver optimal performance.
      Please note: The tyres can also be used on other vehicles.



      Lamellas

      Lamellas are fine notches in the tread which act like little micro-grabbers. In winter tyres, for example, they increase traction when driving and braking. A good number of lamellas is an important condition for good grip in wintery road conditions. These provide optimal interlinking with the road surface. In modern lamella systems, the lamellas become stiff under pressure, thus ensuring better driving performance. Compared to summer tyres, this means winter tyres have

      • better grip
      • on ice and snow, plus better braking behaviour
      • , improved traction
      • , more precise communication with the vehicle when steering
      • , plus safer and generally better driving performance.



      Lateral run-out

      A rim can be affected by lateral run out due to external factors, for example, driving quickly over a kerb stone, or an accident. The rim is then warped in the direction of travel.



      LI: Load Index

      Load Index is generally a two digit number on the end of the size classification, e.g. 175/70 R 13 82 T. The number 82 indicates the load index of the tyre. For example, Load Index 82 means 475 kg load per tyre.



      LK: Bolt circle diameter

      The bolt circle on a rim consists of the holes through which the rims are attached to the vehicle using wheel nuts or bolts. You get the bolt circle diameter by measuring from one hole to the opposite hole. With 5 hole rims you can select one of the two furthest holes.



      LLR: Low Rolling Resistance

      The manufacturer Dunlop call their low roll resistance tyres "Low Rolling Resistance" (LLR). Please note: Tyres optimised for rolling resistance are also available from other manufacturers e.g. the Michelin GRNX range.



      Low profile tyres

      The profile of a tyre describes the ratio of the side height to the width of the contact area. The balloon tyres commonly used in the 20’s with a height to width ratio of almost 1:1 gave way to low profile tyres (up to 0.15 to 1) a long time ago.
      The term low profile tyre applies when the side height is less than 80% of the tyre width. This definition was created in the 70’s, and much has changed in the car industry since then. So nowadays the most common tyre on mid-range cars is size 205/55R16, which can no longer really be regarded as “low profile”
      There is no official definition for low profile tyres. It is fair to say that tyres in the range 50 to 55 could be classed as low profile, depending on the tyre width. These tyres frequently have a flange shield.



      Low resistance tyres

      Tyres with low rolling resistance thanks to new compound technologies are called low resistance tyres. The lower the rolling resistance, the lower the fuel consumption.



      LR

      Special tyre id. for original Pirelli tyres for Land Rover.



      LS

      These tyres have been developed and manufactured according to certain specifications and requirements of the car manufacturer Lotus.
      We recommend fitting four of the same tyres, so that the tyres can deliver optimal performance.
      Please note: The tyres can also be used on other vehicles.



      LT: Light Truck

      Reinforced tyres for commercial vehicles such as vans.



      M+S, M&S, M.S.: Mud and snow

      The letters M+S identify winter tyres and winter-ready all weather tyres. On some products there is also a snowflake symbol. M+S tyres with a snowflake meet a high quality standard. Their particular qualities come into their own at temperatures of 7° C. Summer tyres lose grip and hold at low temperatures because of their rubber compound, leading to increased braking distances, on dry or wet road surfaces. Braking distances on snow are up to 20% shorter than with summer tyres. With wide base tyres this effect comes into play at 10° C. Moreover ABS, ESP or TCS do not help here, as they are purely electronic aids. They cannot replace winter tyres. However, it is important that winter tyres have adequate tread depth. If this is under 4 mm, then the risk of aquaplaning increases significantly, traction and braking performance fall noticeably, and driving properties only reach the same level as summer tyres. Since 2010 it has been compulsory to fit winter tyres in wintery road conditions. Winter tyres are more suitable for wintery road conditions because of their special cold-resistant rubber compound. This means the car grips the road perfectly even at the lowest temperatures. The tread profile which is perfectly adapted to poor weather conditions also minimises the risk of aquaplaning and gives perfect grip on ice and snow. Larger grooves in the tread and extra lamellas guarantee additional stability when moving quickly between snowy, wet, or dry roads. We have the right winter tyres for your car. Please also refer to ABS, ESP and TCS



      M/C

      The abbreviation M/C indicates that the tyre in question is for a motorbike. This designation is compulsory in America, and also applies to scooters.



      M3

      Tyres with this designation have been developed and manufactured according to certain specifications and requirements of the car manufacturer BMW. They are designed as original equipment for the M3 series.
      We recommend fitting four of the same tyres, so that the tyres can deliver optimal performance.Please note: The tyres can also be used on other vehicles.



      Main groove

      The main grooves are usually located in the middle of a tyre, and the wear indicator is also located here.



      Manufacturer tie-in

      Manufacturer tie-in means that the car manufacturer only authorises certain tyre makers for a model. Tyre makers and tyre types authorised by the manufacturer are shown in the vehicle registration documents, or stated in a wheel report in the case of a subsequent change. (See also General Operating Licence). Since the start of 2000, any manufacturer tie-ins for cars have been abolished. Regardless of any entry in the documentation, every tyre maker is authorised. The exception is pure ZR tyres, these require the authorisation from the manufacturer and an entry in the documentation.



      Matching

      Matching is part of the tyre fitting process which helps the wheels turn in the best possible way. Any irregularities in the roundness of the wheels and tyres are combined in such a way that they more or less balance each other out. Matching is carried out before the actual wheel balancing.



      MC, MC1

      Tyres with this designation have been developed and manufactured according to certain specifications and requirements of the car manufacturer McLaren.
      We recommend fitting four of the same tyres, so that the tyres can deliver optimal performance.
      Please note: The tyres can also be used on other vehicles.



      MGT

      Tyres with this code were specially developed as original equipment for the Maserati Quattroporte.



      Michelin Acoustic Technology (MAT)

      Michelin Acoustic Technology (MAT) reduces vibration in the interior cavity of the tire, thereby limiting the volume of rolling noise. Inside the tire is a special polyurethane foam which can reduce noise levels by up to 20%, depending on the vehicle.



      Mileage

      Mileage means the active life span of a tyre before it has to be replaced. This depends on the construction and quality of the tyre, as well as the type of vehicle, type of driving, UV radiation, storage and many other factors. The tyres on the drive axle lock up more quickly, as they are driven more strongly by the increased slip.
      The following applies across the whole EU: The legally required minimum tread depth is 1.6 mm.



      Minimum tread depth

      For cars, vans, lorries and motorbikes, a minimum tread depth of 1.6 mm applies right across Europe. This minimum depth must be present over the whole tyre contact area. When a tyre approaches this legally required minimum tread depth, braking distance in the wet increases, and there is a higher risk of aquaplaning. The braking distance when aquaplaning with a tyre with the minimum tread depth of 1.6 mm is double that of a brand new tyre. For safety reasons, summer tyres should be replaced when tread depth is 2 mm, wide base tyres when it is 3 mm and winter tyres when it is 4 mm.



      Mixed tyres

      Mixed tyres is an informal term with several meanings.
      Legally, mixed tyres means the simultaneous use of radial and diagonal tyres on the same vehicle. This use of mixed tyres is not permitted.
      In addition, mixed tyres can refer to the use of different sizes of tyres at the same time on a vehicle. This is fundamentally banned with regard to cars. One exception to this is where different sizes of tyres are fitted per axle on some sports cars. This is explicitly stated in the car’s paperwork or the rim’s General Operating Licence. It is only acceptable to use a spare wheel of a different size for a short period of time. In this case, please note the instructions on the spare wheel.
      A third interpretation of “mixed tyres” is the simultaneous use of tyres of the same size, but with different tyre profiles. This is permitted. Winter and summer tyres may also be mixed. However, neither of these is recommended: Given the different driving properties of various tyre profiles, the vehicle might pull in a certain direction when braking for example, or behave differently when cornering left or right. Moreover, cars may only be driven in winter conditions with “M+S” tyres.
      In general, tyres with the same profile should be fitted to the same axle. The tread depth on opposing tyres should not be too different.
      This applies particularly to 4 wheel drive vehicles. In this case, all the tyres should have the same profile and similar tread depth, to avoid any damage to the centre differential. Please note the instructions in your user manual.



      MO, MO1

      Tyres with this designation have been developed and manufactured according to certain specifications and requirements of the car manufacturer Mercedes.
      We recommend fitting four of the same tyres, so that the tyres can deliver optimal performance.
      Please note: The tyres can also be used on other vehicles.



      MST

      This abbreviation stands for “Multi Service Tyre” with regard to motorbike tyres. Tyres with this designation are suitable for use on various surfaces.



      MT, M/T

      The abbreviation MT stands for Mud-Terrain. Off road tyres with this additional code have an especially rough tread, which provides traction even in deep mud.



      Multi part rims

      The three part rim consists of a wheel star, an outer flange and an inner flange. The three parts are screwed, riveted or welded together. The two part rim consists of a) Wheel star, base or b) wheel star with outer flange and base with inner flange (moulded in one piece). Both pieces are screwed to the rim base.



      N0, N1, N2, N3, N4, N5, N6, N7

      These abbreviations stand for Porsche specifications. New Porsche vehicles fitted with approved Pirelli tyres come with this special marking. These tyres have been developed and manufactured according to certain specifications and requirements of the car manufacturer.
      We recommend fitting four of the same tyres, so that the tyres can deliver optimal performance.
      Please note: The tyres can also be used on other vehicles.



      Nature-Based High-Performance Vegetable Oil

      This new technology from Nexen was developed using oil derived from natural, sustainable substances instead of fossil fuels. During processing, it is mixed with silica oil to reduce its viscosity and to improve both machinability and dispersibility. This technology makes the tyre eco-friendly and fuel-efficient, with improved snow and ice performance.



      NEO-T01

      Falken’s high-end production technology with advanced tyre architecture, combining innovative materials and perfecting tyre shape uniformity. It enhances comfort and improves the performance by reducing tyre weight and rolling resistance.



      NHS: Not For Highway Service

      Not for Highway Service (NHS) means that tyres marked NHS, and without any service description, may not be used on public roads.



      No LBL: No Label

      The abbreviation No LBL stands for a tyre which has no coloured lettering on the side wall. This is naturally only used when that tyre is also available with coloured lettering.



      Nokian Aramid Sidewall

      Aramid is a polymer plastic, characterised by its high durability. Tyres with Nokian Sidewall technology are highly resistantto damage and abrasion. Compared to conventional tyres,  Nokian Sidewall technology tyres have sturdier sidewalls which reduce the impact of bumps and save the tyre, the rim and the vehicle.



      Non-Marking

      Non marking tyres are tyres designed for a clean environment, as they do not leave any marks (stripes or streaks). For example, they are fitted to vehicles used in warehouses in the grocery sector or in hospitals.



      NT

      On Bridgestone motorbike tyres, NT stands for “New Technology”. Tyres with this identifier are different from their predecessors in terms of improvements to stability, grip, handling and wear.



      NW, NWW: Narrow White Wall

      Specially designed side wall lettering with narrow white stripe.



      NWS: Narrow White Stripe

      Special design of the side wall. Tyres with a narrow white stripe on the side wall.



      OBL: Outlined Black Lettering

      Special design of side wall lettering, with a white surround to the letters.



      OE identical wheels

      An OE identical wheel is a steel wheel which was produced according to the same manufacturing specifications as the standard wheel fitted by the car manufacturer. The only difference between an OE identical wheel and the standard wheel originally fitted is the missing manufacturer trade mark and part number. An additional General Operating Licence is not required.



      OE: Original Equipment

      Original equipment: refers to tyres which have been developed according to the requirements of a vehicle manufacturer, for a certain model. The vehicle in question is delivered with these tyres.
      We recommend fitting four of the same tyres, so that the tyres can deliver optimal performance.
      Please note: The tyres can also be used on other vehicles.



      Off road tyres

      Off-road tyres are special tyres for use off-road. Tyres for mud, sand specialists, all rounders for road and off-road with M+S id, winter tyres, and also high performance road tyres are all available.



      Off road tyres

      Off road tyres are tyres with special properties for use away from public roads and cross-country.
      Please note: These tyres come in both imperial and flotation dimensions.



      OGL: Outlined Golden Lettering

      Special design of side wall lettering, with gold contoured letters.



      Orange Oil Technology

      Orange Oil is the technology that delivers fuel efficient and high performance driving for sports cars. It also solves the grip on low rolling resistance. Orange Oil comes from the orange peel and this keeps the rubber tyre compound soft and flexible. It makes the tires work in cold and wet conditions where the rubber normally loses grip.



      ORBL: Outlined Raised Black Lettering

      Special design of side wall lettering, with slightly raised black contoured letters.



      ORWL: Outline Raised White Lettering

      Special design of side wall lettering, slightly raised, white, contoured letters.



      Over inflation

      Too much air pressure is just as damaging as too little. Shock absorbers and comfort suffer, grip declines and the tyres also generally wear faster and unevenly (centre wear).



      Over-steer

      Over-steer is the term used to describe when the rear wheels lose grip before the front wheels. The vehicle swerves at the back and skids out of the corner.
      Driver assist systems such as ESP try to minimise this behaviour.



      OWL: Outline White Lettering

      Special design of side wall lettering, with white contoured letters.



      OWT: Outline White Lettering

      Special design of side wall lettering, with white contoured letters.



      P: Passenger

      The letter “P” on tyres from the USA stands for private car. This differentiates them explicitly from LT tyres for commercial vehicles. This is particularly useful where sizes overlap.



      PAX-System

      The PAX system is an emergency running system which uses special rims, support rings and tyres in place of reinforced side walls. The spring of the tyre is comparable with a normal tyre. When there is a sudden loss of pressure, you can keep driving on the rim ring. In the event of a flat, top speed is restricted to 80 km/h and there is a limit on permitted mileage.
      Please note: Support ring systems such as the PAX system from Michelin require special rims, specially adapted fitting equipment and mechanics who are specially trained in this type of fitting. Please ask your tyre specialist if this service is available.



      Pirelli Color Edition

      This special characteristic offers the exclusive possibility to personalize your Pirelli tyre within the range of 4 different colours in order to make your care unique. The 4 colours available for this special edition are: Red, Silver, White, Yellow.



      PNCS

      PNCS - Pirelli Noise Cancelling System. These tyres are designed to be  as quiet as possible. PNCS Tyresare fitted as original equipment in some Audi and Range Rover cars.



      POR Tyres

      "Professional Off-Road" abbreviation: tyres for commercial traffic use. POR tyres are specially designed for bad rolling conditions or for deteriorated roads conditions. Information: POR tyres do not have EU labels as they do not meet the tyre EU labeling directives.



      POR-Tyres

      POR is an abbreviation for Professional-Off-Road: Tyres for commercial use. The tyres are designed especially for poor roadconditions. Please note: POR Tyres do not have an EU-Label, as they do not conform with EU tyre label guidelines.



      PR-code, Ply-Rating, Ply Rating

      PR stands for "Ply-Rating".
      This originally referred to the number of layers of cotton cord in the carcass. The more layers of cord, the greater the strength. As stronger materials were introduced for the layers, the term no longer related to the actual number of cord layers. So a tyre with a PR of 8 might only have 4 layers of nylon cord, corresponding to the strength of eight cotton layers.
      Nowadays, the strength of road tyres is indicated by the load and speed indices, instead of ply rating.



      Profile

      The profile ratio of a tyre is shown as a percentage. It shows the height of the tyre as a proportion of the width and is shown in the dimensions of the tyre.
      For example: A tyre size 205/55 R16 is 205 mm wide and the side height is 55% of the width.



      PSWW: Pinstripe Whitewall

      Special design of the side wall with a thin white pinstripe.



      Racing tyres

      Race tyres are tyres which are only suitable for the race track. They are not approved for use on public roads.



      Radial tyres

      With radial tyres the cord piles run radially inside the carcass, at a right angle to the running surface. The radial position of the cord piles give a greater contact area compared to diagonal tyres. This has major advantages for almost all driving properties:

      • mileage
      • grip in the wet
      • driving precision
      • grip when cornering
      • comfort

      Radial tyres were introduced by Michelin in 1948 under the name “X-Technology” and are now the standard for cars and lorries.



      Radius, static

      The height of the wheel measured from the centre to the ground is known as the static radius. It is always measured with the same load on the tyres and pressure conditions.



      RBB, RG, RL, RN, RU, RW

      These abbreviations are found on motorbike tyres. A motorbike tyre is tested on each motorbike it is due to be approved for. So for example if a motorbike becomes unsteady as certain speeds, the tyre will be adapted. This alignment can take the form of a different carcass development or an amended rubber compound.
      In general, only motorbike tyres which have full additional clearance in the vehicle licence or have this additional clearance identification for that motorbike should be used.



      RBL: Raised Black Lettering

      Special design of side wall lettering, slightly raised black letters.



      RBT: Raised Black Tubeless

      Special design of side wall lettering, slightly raised black letters.



      Red Letter: Red Lettering

      Special design of side wall lettering, with red letters.



      RED: Red Sidewall

      Tyres with a special red side wall.



      Refitting

      While we often refer to refitting summer or winter tyres, refitting really means replacing the standard tyres with wider tyres and rims.
      When refitting wheel/tyre combinations, you should always bear in mind the permitted size, conditions and test certificates.



      Regrooving

      Regrooving refers to a one-off deepening of the tread grooves, in order to increase profile depth. This is considered as part of the manufacturing process of the tyre. Regrooving is only allowed on commercial vehicle tyres which have "REGROOVABLE" on the side. Regrooved tyres may only be fitted to the steering axle. This also applies to the spare wheel. Regrooving should only be carried out by an expert in accordance with the manufacturers guidelines.



      Reinforced, reinf, RF, RFD, XL, EL

      So called reinforced tyres are specially strengthened tyres which are designed to carry heavier loads, for example on vans, small buses and off-road vehicles.
      Fitting alone does not automatically increase load-bearing capacity however, they also require a corresponding higher tyre pressure. In addition, the load index figure shown in the vehicle’s paperwork will apply. Some tyre manufacturers also use other designations for their reinforced tyres, such as XL/EL (extra load) or RFD.
      Caution, several meanings: With some manufacturers “RF” also stands for “runflat”.
      Caution: RF-/XL tyres are not C tyres, even if they resemble them with regard to size and load index. Therefore you should check the paperwork for your vehicle or ask the manufacturer which tyres you can use.



      Repairing damage to a tyre

      Nowadays, tyres are very durable. However, they can be damaged by external factors. The most common causes are:

      • tyre pressure is too low
      • damage caused by going over a kerb
      • damage by a foreign body
      • damage from oil, fuel, and tar
      .
      Many forms of damage are visible to the naked eye, even to a non-expert. So you should make the effort to inspect your tyres every so often. Tyre specialists also offer low-cost tyre checks.
      Cuts, splits, lumps or broken tread are all cause for concern, as well as any penetrating foreign bodies such as nails.
      Uneven wear of the running surface is frequently caused by wear and tear of parts in the chassis or steering. But the brakes or an imbalance in the wheels can cause tyre damage of this kind.
      If you find any kind of damage or irregularity in your tyres, you should refer to your tyre specialist as soon as possible. Some kinds of tyre damage can be repaired, saving money and resources. it is not possible to make a global statement about what damage can be repaired without endangering driving safety. Often it is inevitable that the damaged tyre must be replaced. Ultimately, only an expert can judge this.



      Replacement Tire Monitor (RTM)

      Unique marking that visually shows the need to replace the tire by changing from “Replacement Tire Monitor” to “Replace Tire” based on tread wear.



      Replacing tyres

      Fundamentally, tyres must be replaced when the tread depth reaches the legal minimum. In general, tyres (for example spare tyres) should not be more than six years old. Any replacements due to wear and tear should be done axle by axle.
      Please bear in mind equal profile depth, type of profile and manufacturer. Never buy or fit used tyres where you don’t know where they came from.



      Requirements profile

      All tyres must satisfy certain requirements. So for example, load bearing strength must be guaranteed as well as the highest possible levels of driving force, braking power and lateral strength both on dry roads, as well as on damp surfaces, in the wet and on snow or ice.
      Other requirements are: Strength at high-speed, robustness, abrasion resistance, low rolling resistance, low noise production, suspension properties, favourable driving behaviour, resistance to ageing.



      Retreading

      When the running surface of a tyre reaches the limit of wear, but the other components of the tyre are unaffected, the tyre can be retreaded. A legal condition of this is that the side wall must be marked “retreadable”.
      When retreading, the carcass, steel belt and side wall are initially checked for faults. Then the worn running surface is removed and replaced with a new one. This can be done by cold or hot vulcanisation. The side wall is then marked “retread”.
      High quality retreads are a low-cost alternative particularly in the commercial vehicle area.



      Ridge N Flex

      Under the term “Ridge N Flex”, Michelin combines three innovations for winter tyres which together should offer maximum grip and steering precision. The tread is furnished with numerous profile edges (Maxi Edge) arranged at various angles (0°, 15°, 30°, 40°, -25°), which enable strong dovetailing with the ground. Specially designed, self-blocking lamellae (StabiliGrip) stabilise the tread bars and improve steering precision. And the rubber compound (HelioCompound) furnished with silica and sunflower oil remains supple and flexible even at low temperatures and improves grip on winter roads.



      Rim assessment certificate

      The rim assessment certifies the test properties such as the strength of the rim. It is required for registering the wheels at a test centre.



      Rim base

      The rim base is the area between the rim flanges. This is where the width of the rim is measured. As with rim diameter, width is measured in inches.



      Rim classification

      The common international size specifications for rims (e.g. 7Jx15) indicate the width from flange to flange (in this case 7 inches) as well as the height (in this case 15 inches). The “J” stands for the shape of the hump.



      Rim contour

      Rim contour or rim profile means the rim’s construction type. For example, “J” describes an asymmetric base.



      Rim diameter

      The rim diameter is the area the tyre sits around. It binds (seals) the inner radius of the tyre and thus connects the rim to the tyre.



      Rim flange

      The rim flange is the outward bending edge of the rim. Weights may be attached to this to help balance the wheels.



      Rim protection

      The rim protection on a tyre consists of a rubber strip which runs along the ridge on the outer sidewall. It protrudes somewhat over the edge of the rim and thus protects the rim e.g. when the tyre comes in contact with the kerb. Depending on the design and the tyre-rim combination being used, the rubber strip can also protect the sensitive sidewall from being damaged. The protective function is effective at low speeds, for example when parking. If the rubber strip is badly damaged or if parts of it are torn or broken off, the tyre should be checked for additional damage. Many tyre manufacturers use their own designations and abbreviations. The use of a rubber strip as rim protection is neveltheless the same for all of them. Common designations are: rim protection strip (FSL, FL, ML, MFS, MFSL), rim rib (FR), rim protection bar (RPB), fringe protector (FP).



      Rim shoulder

      The area on the rim between the rim flange and hump which the tyre sits on is known as the rim shoulder.



      Rim width

      The interior size of the rim is measured between the rim flanges.



      Rims

      The rim holds the tyre. Generally steel is used in the manufacturing process. In addition there are light alloy wheels made from aluminium or magnesium alloys. These have better run-out accuracy, reduce the weight of the unsprung mass and improve the appearance of the vehicle.For examplefor rim size: 6Jx15 H2 = 6 inch rim width, flange design "J", 15 inch diameter, hump design "H2"



      RL: Raised Letters

      Special design of the side wall with raised, black lettering.



      RO1, RO2

      These markings stand for a special Audi specification, amongst others for R8, RS4, RS5, RS6. These tyres have been developed according to certain specifications and requirements of the car manufacturer.
      We recommend fitting four of the same tyres, so that the tyres can deliver optimal performance.
      Please note: The tyres can also be used on other vehicles.



      ROBL: Raised Outlined Black Lettering

      Special design of side wall lettering, slightly raised. contoured, black letters.



      Rockproof

      “Rockproof” is a summer tyre from Nokian for light trucks and SUVs which are developed for use in difficult conditions, e.g. in forests, quarries, mining regions, on gravel roads. The high cut resistance of the rubber compound and increased thickness of the upper sidewalls should ensure robustness and a long tyre lifespan. Additionally, “Aramid Sidewall Technology” is employed: Aramid fibres manufactured from polymer plastic, also used in e.g. the security sector and the aeroplane industry due to their high rigidity, strengthen the sidewalls for protection against bumps and cuts. Tread bar supports and stone deflectors in the groves are additional measures for improving stability and safety and preventing tyre damage.



      Rolling circumference

      Rolling circumference indicates the distanced covered by any point on the tread during one revolution of a wheel. Therefore the rolling circumference depends on the diameter of the tyre. It has an influence on the transmission and also the tachometer drive. Based on standard production tyres, a tyre with a smaller rolling circumference will tend towards shorter transmission. This has a positive influence on acceleration, but the rev counter could well be in the red at top speed. In addition, the smaller tyres lead to increased speedometer signal swift. Tolerances of plus 1.5% and minus 2.5% are acceptable. Where there are larger deviations, the speedometer must be corrected, at the very least.



      Rolling resistance

      Rolling resistance indicates the force needed to move the tyre. Winter tyres have a higher rolling resistance than summer tyres due to their deeper, more heavily treaded profile and their higher pressure per square centimetre. Load and tyre pressure also come into consideration.



      ROWL: Raised Outline White Lettering

      Special design of side wall lettering, slightly raised, contoured. white letters.



      RRBL: Recessed Raised Black Lettering

      Special design of side wall lettering, slightly raised black letters with recess.



      RSB: Raised Serrated Band

      Special design of the side wall. The lettering is serrated inside the edge.



      Rubber compounds

      A tyre can consist of up to 16 different rubber compounds. However, the tyre manufacturers keep the exact composition to themselves. In order to make a good tyre, a lot is demanded of the rubber compound: low abrasion, tear-resistance, anti-slip properties, low rolling resistance, dynamic stability, air tightness and resistance to ageing.



      Rubber types

      There are various kinds of rubber used in tyre manufacturing.
      As well as natural rubber (harvested from the sap of the hevea tree in equatorial plantations), we are now turning increasingly to artificial or synthetic rubber.



      Run-out accuracy

      Good, circular running of tyres is important for comfort and permanent, complete contact between the contact area and the road surface.
      If the wheel does not run in a circle, the driver will feel this in the steering wheel. A tyre specialist can check the roundness of your tyres and help if required.



      Runflat, RSC, RFT, SSR, DSST, ZP, RF, HRS, ROF, EMT, TD, MOE, MO Ext.

      Runflat tyres (manufacturers use a variety of names) are tyres with emergency running properties, which allow the motorist to keep driving for a limited distance when tyre pressure is lost and / or tyre pressure is too low. However, the vehicle must also be fitted with a TPCS. The runflat system works with a reinforced side wall which more or less keeps its shape in the event of a loss of pressure. These means the driver can keep control of his vehicle if pressure is suddenly lost. Travelling at max 80 km/h, he can then look for the nearest tyre specialist within a radius of 80 km.
      Runflat technology offers the driver a clearly recognisable benefit, and a real plus in safety and comfort. In addition, you don’t have to change the wheel when you have a flat, removing any need for a spare wheel. All runflat tyres have the common RSC (Runflat System Component) symbol on their sidewall.



      Running surface

      The running surface is the only part of the vehicle which is in contact with the road surface, and is responsible for transmission of power, alongside the other tyre components. This means the contact area of the tyre - the part of the running surface which touches the road surface - is not much bigger than a postcard!
      The running surface must handle acceleration and braking power in the direction of travel, and also lateral force when steering and cornering. The performance of the running surface is largely determined by the sub-structure (belt, carcass), the bead and side area, but the design of the tread is absolutely critical.



      RWL: Raised White Letter

      Special design of the side wall with raised, white lettering.



      S identification

      Since 01/10/2009, only tyres with an “S” on the side can be sold. This stands for “sound” and indicates tyres with low road noise. There is, however an interim ruling, which allows dealers to sell tyres without the “S” after the deadline of the 01/10/2009. A condition of this is an appropriate certificate from an approval authority stating that the tyre meets the noise level standard even without the explicit identifier.
      The ruling only applied to tyres up to 185 mm wide. For car tyres 185 mm to 205 mm wide the sales ban has applied since the 01/10/2010, and for wide base tyres from 215 mm, since the 01/10/2011.



      S1

      This code stands for the original equipment on Peugeot models. These kind of tyres have been developed and manufactured according to certain specifications and requirements of the car manufacturer.
      We recommend fitting four of the same tyres, so that the tyres can deliver optimal performance.
      Pleas note: The tyres can also be used on other vehicles.



      Saw tooth

      Saw tooth is the name tyre technicians give to the uneven abrasions on the horizontal edge of tread blocks in the direction of travel of the tyre. At an advanced stage, saw teeth can often cause serious vibrations in the steering wheel and also road noise.
      As saw teeth start to from, it can help to change the wheels between the front and rear axles. In a severe case however, you should ask or advice at your tyre specialist.



      SBL: Serrated Black Lettering

      Special design of the side wall with serrated black lettering.



      Sealguard Puncture Protection

      The Sealguard technology developed by Hankook, self-seals punctures of up to 5mm on the running surface.  The tyre is protected from so many causes of punctures that, as per Hankook, it it not necessary to have an additional spare tyre. The technology is used in the Hankook Ventus Prime2 Sealguard and is fitted as original equipment in many Volkswagen models.



      Self Seal

      Self Seal Technology refers to tyres which can re-seal themselves in the event of damage, e.g. by a nail puncture. The tyre contains a special polymer coating which, in the event of a puncture, embeds itself in the damaged area of the running surface, sealing the hole. However, the tyre should be replaced as soon as possible.

      Self Seal Technology is available from Pirelli (Seal Inside), Michelin (SelfSeal), Continental, (ContiSeal), Hankook (Sealguard), Bridgestone (Driveguard), and other manufacturers, in specific tread patterns.



      Self supporting tyres

      Better known as runflat tyres. All self-supporting tyres have a reinforced sub-structure, an adapted carcass and belt, as well as stiffened side walls and bead areas.



      SET

      The letters SET indicate that the tyres come with an inner tube (occasionally also a flap)



      Shoulder abrasion

      Shoulder abrasion refers to the high level of abrasion on the shoulders of the tyre compared to the middle of the tread. Increased shoulder abrasion can occur both on one side in isolation and both sides at the same time.
      Abrasion on one shoulder occurs mainly when the position of the wheel in relation to the road surface is not ideal. In this case, tracking and camber should be checked with an axle measurement.
      Shoulder abrasion on both sides is mainly caused by low tyre pressure or over loading.
      On wide base tyres, more shoulder abrasion is normal.



      Side wall

      All the information relating to the tyre is located on the side wall. In order to avoid any damage, it may be fitted with a flange shield on the outside. External damage can occur when driving hard over a kerb. In addition, this can also break the integrated carcass fibres. Alongside the tyre shoulders, the side walls flex the most and are therefore exposed to very high loads.



      SilentArmor Technology

      Latest technology innovation for SUV drives that gives a strong and tough tyre combined with comfortable, quite and performance of a car. The super absorbent layer between the tyre tread and underlying belts provides a smooth and quite riding experience.



      Silica compound

      Silica is the name for the salt of silicic acid. Using silica stabilises the network of connections between the individual materials in the rubber compound. Compared to regular structures, silica increases the strength of the material. This reduces wear and tear, and increases mileage. The tyre also grips the road better, as the compound can be designed to be softer due to its increased strength.



      Slick tyres

      Slick tyres are racing tyres without any tread.



      Slip

      Slip is the difference between the geometric circumference of the wheel and the distance actually covered by one revolution of the wheel. Slip is 100% when the wheels spin or lock. So the higher the drive or braking force, the greater the slip. Even if you don’t notice it: There is always a small degree of slip when driving, and the tyre rubs on the road surface with every revolution - hence the wear and tear on tyres.



      Slip angle

      Slip angle refers to the difference between the position of the wheel and actual direction of travel. A high slip angle requires a lot of steering lock in order to bring about a change in direction. A certain degree of slip angle is needed for the wheel to generate cornering force. The stiffer the tyre construction, the lower the angle, and the safer the driving behaviour.



      Smart Seal Technology

      This feature prevents air loss from the tyre if it is penetrated by a foreign object; if the object is then dislodged, the tyre seals itself. This is done by means of a sticky layer located in the inner liner area. Nexen SmartSeal technology seals punctures less than 5mm in diameter in the tread area.



      SmartTRED

      SmartTRED technology from Goodyear guarantees excellent traction in winter and optimum grip in summer. The combination of stable shoulder blocks, strong lamellas in the middle, and a special base contact area ensures self-activating, flexible adaptation of the tyre to changing road conditions.



      Snow chains

      Snow chains are a driving aid for vehicles on snow covered roods or muddy ground, and they are mounted on the tyres. We differentiate between full snow chains and start assistance. Snow chains improve traction on ice and snow, and the direction of the wheels. They consist of chain links made from hardened steel. Depending on the chain pattern, you can choose from ladder chains, zig zag chains, or diamond pattern chain, which is the quietest and safest type. Fitting is made easier by a so-called endless chain. You should always watch your top speed when driving with snow chains!



      Snowflake symbol, severe snow

      On some winter or all-weather tyres there is also a snowflake symbol. M+S tyres with a snowflake meet a high quality standard and help easy identification of tyres with certified winter properties. The official snowflake stamp only comes in combination with the M+S marking.



      SnowProtect Technology

      This unique technology consists of slats with locking bar in the upper area, high slat density and flexible profile blocks. This features excellent braking performance on snowy roads.



      SoundComfort Technology

      Containing a noise absorbing foam attached to the innerliner of the tyre, this technology reduces vehicle noise up to 4db(A), featuring a light and durable solution, maintained over the entyre life of the tyre.



      SOWL: Slanted Outlined White Lettering

      Specially designed side wall lettering with serrated, contoured white letters.



      Spare wheel, replacement wheel, replacement tyre, emergency wheel, emergency tyres

      The spare wheel is a slim wheel mainly kept under the boot, or under the vehicle itself. In the event of a flat, it can be put on the vehicle in order to get to the nearest garage. When driving with a spare wheel, the speed indicated on the spare tyre should not be exceeded. The spare wheel should only be used for a short period of time, in order to avoid any damage to the axle differential.
      When you check your tyre pressure, you should also check the pressure in your spare wheel. This means your spare wheel will be ready for action in the event of a puncture.
      Caution: If you normally drive on alloy wheels, the wheel bolts may not fit the spare wheel. So you should always bring along the bolts for steel wheels.
      An inflatable spare wheel is a special kind of spare which is kept deflated in the car. Before changing wheels it must first be inflated with a compressor.



      Special motorbike identification

      These abbreviations are found on motorbike tyres. A motorbike tyre is tested on each motorbike it is due to be approved for. So for example if a motorbike becomes unsteady as certain speeds, the tyre will be adapted. This alignment can take the form of a different carcass development or an amended rubber compound.
      In general, only motorbike tyres which have full special clearance in the vehicle licence or have this special clearance identification for that motorbike should be used.



      Speed index

      The designation on the side wall of every tyre includes a letter which indicates the permitted speed which this tyre is suitable for. Which tyre is suitable for your vehicle is shown in the registration document or the vehicle licence part 1 and the CoC paperwork:
      For example: 195/65 R 15 H: H = up to 210 km/h. The following letters are found most frequently in the car tyre section for the speed index:

      • Q = max. 160 km/h
      • R = max. 170 km/h
      • S = max. 180 km/h
      • T = max. 190 km/h
      • H = max. 210 km/h
      • V = max. 240 km/h
      • W = max. 270 km/h
      • Y = max. 300 km/h
      • ZR = over 240 km/h



      Spikes

      Additional vulcanised steel or hardened metal pins which stick out 1.5 - 2 mm from the running surface in the tread of winter tyres are known as spikes. These are designed to give the vehicle more grip, above all on icy roads.
      The disadvantage is that tyres with spikes have much less grip on dry roads that an a pure rubber tyre. In addition, there is much greater wear on the road, as spikes cause cracks on the road more quickly.
      For these reasons, they are only permitted at certain times of the year, depending on the country in question. In Germany and some other countries they are generally banned. In addition, speed restrictions are generally enforced. The speed limit is 80 km/h on main roads and 100km/h on motorways. Spikes are permitted on vehicles up to 3.5 t.
      When driving with spikes it should be noted that road noise increases considerably, and that braking distance on a dry road surface also increases.
      Note: Tyres with spike holes or spikes must not be marked with an “S”, as these can not meet the required noise regulations because of the spike holes or spikes.



      SRBL: Serrated Raised Black Lettering

      Specially designed side wall lettering with slightly raised, serrated, black letters.



      StabiliGrip

      Stabiligrip is a winter tyre technology from Michelin which aims to achieve more grip and steering precision through the optimisation of the lamella design. The treads contain a multitude of three-dimensional, self-blocking lamellae, which reach up to the base of the tread, and are arranged at various angles. They stabilise the tread bars and create a large number of gripping edges, which lock into the ground. StabiliGrip Lamellae improve the ability to penetrate the water film, and thus ensure more contact with the road.



      Steering precision

      Steering precision in the context or tyres and vehicles relates to their ability to steer in and out of corners, and also driving behaviour in the corner itself. High performance (Y and ZR) tyres designed for sports driving generally have a high level of steering precision.



      Stopping distance

      Stopping distance is the sum of reaction distance and the actual braking distance.



      Storage

      In summer, winter wheels must be stored properly, and in winter your summer wheels. The easiest for the motorist is to leave his tyres and wheels with the tyre specialist. Not only will the tyres be stored properly here, they can also be checked for damage and cleaned if desired.
      If you want to store your tyres yourself, then you should take on board the following tips: Mark the current position on the vehicle on each tyre:

      • FR = front right,
      • FL = front left,
      • RR = rear right,
      • RL = rear left.

      remove any loose chippings from the treads. Choose a dry, dark, cool storage area, free from petrol, oil, grease and other chemicals. Ideally, stack your wheels on a wheel tree. Alternatively, you can stack your wheels flat on top of each other. In this case. we recommend balancing the wheels before they are fitted on the vehicle. Tyres without rims should be kept upright and turned now and again.



      Studless

      Studless tyres are winter tyres without spikes, which also may not be fitted with spikes.



      Summer tyres

      Compared to winter tyres, the rubber compound in summer tyres is less elastic in order to function more effectively at high temperatures: Rolling resistance and wear are reduced, giving better results with regard to mileage, driving comfort and steering stability. Summer tyres are designed for dry roads, high temperatures, high speeds and the corresponding temperature requirements, as well as damp and wet road surfaces.



      Suspension

      The parts joining the chassis and the wheels are called the suspension. The main task of the suspension is to keep the wheels in contact with the road at all times. This means it determines the road-holding, driving comfort and safety of a vehicle. The wheels can be attached to the suspension individually (independent suspension) or together with an axle (rigid axle). The main components of the suspension are: Transverse control suspension, springs, shock absorbers and stabilisers.



      SUV: Sport Utility Vehicle

      A Sport Utility Vehicle is a vehicle which can be driven both in the town and off-road.



      SVSB: Slanted Vertical Serrated Band

      Specially designed side wall lettering. The side wall is decorated with a ring, which vertical ribs (similar to the underside of some mushrooms.



      SW: Single White

      Tyre with white side wall.



      SWS: Slim White Stripe

      Specially designed side wall with a thin white stripe.



      TCT: Trapezoid Contour Theory

      Trapezoid Contour Theory (TCT) is a tyre technology from Hankook. TCT stands for an innovative design of the tyre tread, based on trapezoid contours. By using a trapezoid shape, driving comfort and safety of the tyre are considerably increased. On sharp corners, there is very little lateral distortion due to the trapezoidal tread.



      Temperature dependency

      Tyre temperature has a considerable influence on the coefficient of friction as well as slip and slip angle. In low temperatures the coefficient of friction is on the low side, but it rises as temperature rises. If operating temperature rises further, the coefficient of friction falls as does the force transferred. The coefficient of friction of rubber is temperature dependent.



      Test certificate, tyre clearance, special tyres

      Accessories not covered by the General Operating Licence are subject to compulsory testing at a test centre. These accessories can only be fitted to a vehicle once authorised. Then they must be entered in the vehicle documentation with the TÜV and the vehicle licencing office.



      TL: Tubeless

      This abbreviation stands for tubeless tyres. In this case the tube is replaced by a inner liner, an air-tight coating. Tubeless tyres are standard nowadays with cars and lorries.



      Toe out

      Tracking describes the angle between the wheels when viewing the car from above. When the wheels point outwards, this is called “toe-out”.
      Toe-out can be used to equalise the driving forces which impel the wheels forwards. This reduces wear and tear on the tyres.



      TOP Indicator Technology

      The TOP(Tread Optimal Performance) Indicator Technology helps users to know whether the profile is still adequate for winter conditions. Tyre profile depth can be easy evaluate without auxiliary tools.



      Torque

      Nuts and bolts on a wheel must be tightened to a certain level. The tighter the better does not always apply to these bolts! If nuts and bolts on a wheel are tightened too much or unevenly, it can deform the wheel bearings, the brake discs and the rim. The wheel nuts and bolts may break off.
      To tighten nuts or bolts properly, use a torque wrench diagonally. You can get these with adjustable torque at any car accessories specialist.
      The torque required is different from vehicle to vehicle and from rim to rim. The correct torque for any original rim will be in the car’s instruction manual, and for after-market rims it will be in the relevant section of the General Operating Licence. It is much safer, and much less effort to leave this to your tyre specialist. He will he happy to tighten the nuts for you after a certain mileage (at least 20 km, 200 km at the most).



      TPMS: Tyre Pressure Monitoring System

      Tyre pressure monitoring systems (TPMS) monitor tyre pressure. They are used in wheel tyre systems with emergency running features. There are direct systems, built onto the valve, and indirect systems, which take the tyre pressure from the wheel revolutions on the ABS sensor.
      TPMS is an EU requirement for all new vehicle registrations up to 3.5 t.
      Other names for TPMS are: Tyre Safety System and RTPMS: Remote Tire Pressure Monitoring System. Moreover, in the USA market, tyre pressure monitoring systems have been a legal requirement on all new vehicles with a registered total weight of up to 4.5t since 2007.



      Tracking

      Tracking refers to the relative position of the wheel when viewed from above. If they are slightly closer at the front than at the rear, then they are called toe-in. If the wheels are closer together at the rear, then they are toe-out. On front wheel drive vehicles, toe-out reduces the influence of driving force on steering, whereas rear wheel drive cars are set up toe-in. The friction between wheel and road tries to push the wheels out on each side, but the power of the front wheel drive tries to push the wheels together. When steering the car into a corner, the slightly negative tracking created by the arrangement of steering linkage and wheel suspension is more pronounced with toe-out: The wheel on the inside of the corner turns more than the one on the outside. This is necessary because the inner wheel describes a tighter circle. This ties in with support of the steering movements and steering force.



      Traction

      Traction is the ability to convert engine power into forward motion by means of interlocking with the road surface. Traction is no problem on dry roads. It only starts to fall in the wet, or on ice and snow. Then the gripping ability of the rubber compound and the tread profile (v-profile, lamella tyres for snow) plays a decisive role.



      Tread compound

      The positive and negative tread of the tyre is made from tread compound. The performance level of a tyre when driving essentially depends on this - in the wet, or in hot conditions, and when transferring lateral or linear power. The tread compound also partly determines mileage and noise properties.



      Tread, tread depth

      Safety depends on the tread of the tyre, particularly tread depth, especially in the wet or in mud or snow. New car tyres have a tread depth of more than 8 mm approx. The legal requirement (§36 StVO) is a minimum tread depth of 1.6 mm. You can check whether this minimum depth has been reached with a tread indicator (a marker in the tread grooves). The location of these markers is indicated by the letters “TWI” on the shoulder of the tyre. If this marker is clearly visible, and is at the same level as the rest of the tread, then they tyre is down to the minimum of 1.6 mm.
      Experts recommend car summer tyres are changed when tread is down to 2mm, wide base tyres should not go below 3 mm, and winter tyres start to lose their effectiveness when tread is down to 4 mm. A driver who allows his tyres to go down to the permitted limit of wear and tear is not just breaking the law, they are also putting their insurance cover at risk.



      TT: Tube Type

      This abbreviation stands for a tyre which needs an inner tube.



      TWI: Tread Wear Indicator

      Tread wear indicators are built into the tread grooves on the running surface. When tread depth is 1.6 mm, they form a continuous bar with the tread itself. The location of these indicators is shown by triangles on the side wall, the letters TWI, or small, brand-specific symbols.



      Twin tyres

      Twin tyres means fitting two tyres on both sides of the axle. Twin tyres are used particularly on the rear axle of commercial vehicles.
      On axles with twin tyres, you should avoid mixing different tyre manufacturers and tread patterns. Only tyres with the same air pressure and dimensions should be used together.
      Caution:For twin tyres, the lower load index applies.



      Tyre age

      Tyre age is determined by two factors:
      On the one hand, small amounts of ozone in the atmosphere penetrate the rubber of the tyre, and affect the sulphur compounds between the rubber molecules. This means the rubber loses its elasticity.
      On the other, tyres also age when they are stored, unused, and they harden, becoming brittle and porous. This can then lead to hairline ageing cracks. Sun, wind and weather, as well as contact with grease, oils and chemicals attack the tyre and speed up the ageing process.



      Tyre checks

      Tyres from the only point of contact between the vehicle and the road. This means they should be checked regularly. The most important things here are tyre pressure and remaining tread depth, which must not be below 1.6 mm in the EU. The correct tyre pressure can be found in the vehicle’s user manual, or from the manufacturer and tyre specialists.
      If a tyre loses an excessive amount of air, then it should be checked out for damage by an expert. He can spot any damage which, if repaired in good time, will improve the safety, comfort and life of the tyre.
      You should check your tyre pressure every other time you refuel at the very least. This is also possible when the tyres are filled with a special gas (e.g. nitrogen). However the special effect of the gas gradually disappears as you top up with normal air.



      Tyre classification, tyre size

      You can interpret the code on the tyre as follows in this example:
      195 / 50 R 15 82 V
      195 = Tyre width in mm
      50 = Tyre profile, ratio of height to width as a percentage
      R = radial construction
      15 = Tyre interior diameter (rim diameter) in inches
      82 = Load-Index (in kg)
      V = Speed-Index



      Tyre insurance

      Tyre damage is irritating and replacing tyres is generally very expensive. To offset this, you can insure your tyres against irreparable damage: whether cuts from shards, tears in the side wall or curb impact.
      The financial outlay for tyre insurance is very manageable, and can be calculated individually, and some insurers allow you to only insure two tyres instead of all four.
      Tyre insurance is particularly worthwhile with regard to high value tyres in the premium range.



      Tyre manufacture

      In order to develop and produce a new tyre, you must go through several steps.
      The focus within tyre manufacture is on:
      the defined compound of different types of rubber and chemical additives,
      production of various cord fibres for the carcass,
      production of the extremely strong steel wire for the belt,
      fixing the bead, constructing the raw tyre as a finished assembly,
      vulcanisation in the heating press and
      comprehensive final checking of every individual tyre.



      Tyre purchase, fitting

      Which tyre is suitable for your car is shown in the registration document or the vehicle licence part 1 and the CoC paperwork. You should only buy and fit the authorised tyres, otherwise your vehicles registration licence will lapse. Basically, the following applies: Tyres should be replaced at least per axle. Tyres from different manufactures, with different treads or different tread depth should not be used on the same axle, as this can lead to uneven driving and braking properties of the vehicle.



      UHP: Ultra High Performance

      Ultra High Performance tyres are very wide, and can withstand speeds of at least 240 km/h (speed index V). Compared to regular tyres, they perform better when changing lanes, and offer better driving stability.



      ULW: Ultra lightweight

      This stands for the ultra light construction of radial tyres which Dunlop introduced in 1994. Tyres made in this way reduce the weight of the vehicle by 12 kg.



      UMS: Ultra Mileage & Safety

      Ultra Mileage and Safety (UMS) technology developed by Hankook sets new standards for the development and production of lorry and bus tyres. UMS guarantees a longer life span and higher mileage, maximum handling and safety, plus optimum comfort and economy.



      Under inflation

      If you drive with too little air in your tyres, you will jeopardise safety and experience a number of disadvantages e.g. damage to long term strength, spongy driving performance, reduced mileage from the tyres, higher fuel consumption. So the following rule of thumb applies: Check your tyre pressure every two weeks, when your tyres are cold.



      Under-steer

      Under-steer is the term used to describe when the front wheels lose grip before the rear wheels. The vehicle skids out of the corner over the front wheels.
      Driver assist systems such as ESP try to minimise this behaviour.



      Uniformity

      Uniformity is what tyre technicians call the manufacturing accuracy of a tyre. Uniformity is an important condition for a wheel to roll perfectly and quietly, without irritating noises and vibrations. The better the uniformity of the tyre, the easier the wheel is to balance.



      URS (Ultra RunFlat System)

      This system incorporates the same principles as RunFlat technology, but this new Nexen technology has added benefits: URS uses Profiled Insert design to disperse the internal stress and filler design, Intensified Insert and Bead, which disperse the internal stress on the flexing parts. Benefits of this new technology include optimal vulcanizing and declining prevention of physical properties.



      UTQG: Uniform Tyre Quality Grading

      The UTQG quality grading established by US department of transport rates the tyre’s performance level based on three criteria: Tread wear, Traction, and Temperature Resistance.
      It only applies to tyres (excluding winter tyres) with a rim diameter of at least 13 inches. The tread wear figure is a comparative value based on wear and tear of a tyre compared to a standard tyre which has been tested on a certified test track under controlled conditions. A tyre with the rating 150 will wear one and a half times more slowly than the standard tyre, which has a tread wear rating of 100. The actual tyre performance depends on the relevant conditions of use, and can deviate substantially from the norm due to driving behaviour, maintenance, different road surface properties and weather conditions.
      The Traction rating is shown by the letters AA, A, B and C in descending order. It indicates the grip properties on wet surfaces, and is measured under controlled conditions on a certified test track.
      Temperature: Temperature is shown by the letters A, B and C. These values show how resistant the tyre is to heat, and how well it can disperse the heat on a pre-determined test wheel under controlled, laboratory conditions. Excessively high temperatures can have a negative effect on the material of a tyre, reduce its life, and cause frequent tyre damage.
      The temperature rating relies on tyres having the correct air pressure, and excludes over-inflation. Excessive speed, incorrect tyre pressure, and over inflation, in isolation or together, can cause a build up of heat or tyre damage.



      Valve

      We differentiate between two types of valve: Rubber valves, which seal off the whole in the rim themselves, and metal valves, which use a grommet for sealing.
      Caution: Valves are very sensitive to dirt, dust and humidity. Therefore, the valve cap must always be screwed on firmly.



      Valve caps

      Valve caps protect the actual valve from dirt and moisture.



      Vector

      Vector is the product name for the innovative all year tyre range from Goodyear.



      Vmax

      Vmax is a range of tyres from Continental, which was specially developed for specially tuned models and super sports cars. These tyres are approved for speeds up to 360 km/h on the road.



      VO

      This marking is found on the side wall of original tyres supplied with Volkswagen models. These tyres have been developed and manufactured according to certain specifications and requirements of the car manufacturer VW.
      We recommend fitting four of the same tyres, so that the tyres can deliver optimal performance.
      Please note: The tyres can also be used on other vehicles.



      VSB: Vertical Serrated Band

      Specially designed side wall lettering which is serrated inside the edge.



      VTS-Lamellas: Variable Thickness Sipe

      Variable Thickness Sipe (VTS) is a lamella system from Michelin for high performance tyres up to 240 km/h - with self blocking lamellas for optimum transmission of power, outstanding handling and steering precision.



      Vulcanisation

      Vulcanisation is the last stage of the tyre production process, also commonly known as “tyre baking” amongst tyre professionals. Not only does the tyre blank get its final tread in the vulcanisation process, the individual tyre components are also combined by the targeted control of pressure and temperature for precise periods, thus becoming elastic rubber. This takes place at 165-200° C and pressure of 12-24 bar for around 9-17 minutes.



      Water penetration

      On wet surfaces, the tyre’s positive blocks have to divert the water through the drainage grooves.



      Wear and tear

      Wear and tear depends on how the tyre ages and level of driving. Durability of the tyre is determined by the driving style, vehicle loading, UV radiation, road conditions and maintenance (air pressure, storage). With the same type of vehicle and tyre, it is possible to find differences in performance of several thousand kilometres.



      Wear indicators, abrasion indicators (TWI, DSI, WSI, VAI)

      In order to make the wear on a tyre visible, manufacturers equip their product with various optical markings. Small rubber bars in the tread grooves or coloured strips, numbers and symbols on the tread show the level of wear. After wear these markings disappear or become visible. The abrasion indicators give information not only on the actual tread depth, but also on the remaining performance, and thus the safety of a tyre regardless of the legal minimum requirements: Thus the disappearance of a water drop marking on a summer tyre means an increased danger of aquaplaning. And winter tyres lose their winter suitability and should be replaced as soon as the ice crystal marking on the tread is no longer visible. Aside from that, abrasion indicators can indicate wear on one side. Most show symbols, signs and abbreviations on the tyre shoulder, where the wear indicators are found in the tread. In addition to the standard abbreviation “TWI” (Tread Wear Indicator), manufacturers also use their own designations for their wear indicators, for example DSI = Driving Safety Indicator, WSI = Winter Safety Indicator, VAI = Visual Alignment Indicator.



      Wear pattern

      The wear pattern of a tyre gives an expert valuable information about whether the tyres are aligned properly, or if there is any damage to the chassis (axle geometry, shock absorber defects etc.). Therefore tyres should be checked regularly by a specialist workshop (around every 10,000 to 15,000 km).



      WearControl Technology

      The two rubber mixtures in the tread provides optimal balance of wet grip and rolling resistance over the entyre tyre life. This results in a shorter braking distance in wet conditions and less fuel consumption.



      Weight specifications

      Unladen weight: Weight of the vehicle when ready for use, weighed without the driver. 75kg for the driver is taken into consideration for commercial vehicles only.
      Vehicle load capacity: Difference between unladen weight and permissible total weight. Permissible total weight: Fixed upper weight limit which a vehicle can reach including load.
      Roof load: When limit when using a roof rack or roof box. Roof load generally lies between 50 and 100 kg. If this is exceeded, there is the risk that the otherwise balanced driving behaviour of a car can become significantly worse, that the rack breaks or comes off after a delay.
      Vertical load: maximum weight capacity of a towbar in a vertical direction. Depending on the type of vehicle, this is normally between 50 and 75 kg.



      Wet weather performance

      When braking in the wet, the tyre must be able to divert the water under the contact area as quickly as possible, in order to prevent aquaplaning. This in mainly influenced by tread pattern, tread depth and grip. Special silica compounds provide increased grip here. On winter tyres, performance in the wet is also helped by lamellas in the tread block.



      Wheel balancing

      Balancing is the process of adding weights to the wheels, in order to ensure circular motion of the wheel. Poorly balanced wheels are excessively tough on tyres, wheel bearings and suspension. Uneven rolling of the wheel makes the whole car vibrate right into the steering wheel, depending on speed. This reduces the contact area, speeding up tyre wear. Pressure on the suspension is also increased.



      Wheel disc

      The wheel disc connects the rim and the wheel hub.



      Wheel load

      Wheel load is the force exerted vertically on a wheel. It is related to the axle load noted in part 1 of the license certificate.



      Wheel sensors

      Wheel sensors measure the revolutions of the individual wheels. This makes them part of, and the most important element of the anti-lock systems, traction and stability control systems of a vehicle.



      Wheel spacers

      In order to widen the tracking of a vehicle, you need wheel spacers which are fitted between the rim and the hub. This allows the rims to stand out further from the wheel arches.



      Wheelbase

      Wheelbase is the distance between the front and rear axle, measured in each case from the centre of the wheel. A relatively long wheelbase allows better seating proportions in the interior of the vehicle, creates short chassis overhangs, improves directional stability and reduces pitching motion of the chassis. As the suspension can be better aligned with a longer wheelbase, driving comfort is improved. However, a shorter wheelbase improves manoeuvrability of a vehicle, leading partly to better control and better cornering.



      Wide base tyres

      Wide base tyres offer a number of advantages over standard tyres. Wide base tyres usually refers to tyres with a profile ratio of 55 and lower (e.g. 205/55 R 16). However, there is no common definition.
      The advantages include a clear improvement in driving stability, considerably better steering precision and better high speed performance.
      Wide base tyres also come into their own in winter: You can stop more quickly on compacted snow caused by high volume of traffic. In contrast, standard tyres come out on top due to their higher contact pressure in deep snow and slush.



      Winter tyres

      Compared to summer tyres, winter tyres can be recognised by their coarser tread and characteristic lamellas. Winter tyres are more suitable than summer tyres for wintery road conditions because of their special cold-resistant rubber compound. This means the vehicle grips the road perfectly, even at the lowest temperatures. The tread profile which is perfectly adapted to poor weather conditions also minimises the risk of aquaplaning and gives perfect grip on ice and snow.
      Larger grooves in the tread and extra lamellas guarantee additional stability when moving quickly between snowy, wet, and dry roads. The letters M+S identify winter tyres and winter-ready all weather tyres. On some products there is also a snowflake symbol. M+S tyres with a snowflake meet a high quality standard: In many European countries, winter tyres are compulsory. This varies from country to country. Since 2010 it has been compulsory in Germany to fit winter tyres in wintery road conditions.



      WL: White Letters

      Specially designed side wall lettering with white letters.



      WLT: White Letters

      Specially designed side wall lettering with white letters.



      WRL: White Raised Letters

      Specially designed side wall lettering with slightly raised, white letters.



      WS: White Stripe

      Specially designed side wall with a white stripe on the side wall.



      WSS: White Side Sign

      Specially designed side wall with a white strip.



      WSW: White Sidewall

      Specially designed white side wall.



      WW: White Wall

      Specially designed white side wall.



      WWW: Wide White Wall

      Specially designed side wall with a broad white strip.



      XC: Cross Country

      Cross Country tyres are off-road motorbike tyres.



      XNW: Extra Narrow White

      Specially designed side wall with a narrow white strip.



      Y Lamellas

      Y Lamellas are a Michelin invention for winter tyres. The sophisticated design of these Y shaped slits in the tread block doubles the volume of tread edge after approx 1/3 of their life span. The result: Even despite declining tread depth, winter grip is exceptionally good.



      Yellow and red dots on tyres

      Some tyre manufacturers use coloured markings on their tyres, such as yellow or red dots. These do notrelate to quality features of the product in question. These markings might relate to various sorting issues from the manufacturer’s different tyre factories. So for example, a manufacturer could track a shipment right through the route to market. However, the manufacturers do not publish any further information about these coloured markings.



      Z Lamellas

      Z Lamellas are Z shaped, arranged to the mid point of the wheel. This results in a supporting effect, which gives good traction, excellent grip and steering precision. Z lamellas are mainly used in winter tyres and in the high performance area. Depending on the performance level desired, same direction and opposite direction Z lamellas designs are available.



      ZR - Tyres

      Pure ZR tyres have no service description. ZR indicates that the tyre is suitable for speeds over 240 km/h, but not does state definitively what speed, at what load and tyre pressure. These figures are calculated and certified individually by the tyre manufacturer, while indicating the vehicle axle load and final speed. However, a service description may also be included on the side of the tyre, indicating the maximum limit of a tyre e.g. “99W”. A ZR tyre is definitely suitable for speeds over 300 km/h. if a letter “Y” in brackets is included, e.g. (109Y)



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