Measuring tyre tread: how to do it right

Whether winter tyres, summer tyres or all-season tyres: the tread depth is decisive for the handling of your car. To ensure safe driving, there is a legal minimum tread depth. However, organisations such as the ADAC recommend something else... Find out in the following guide how to measure the tread depth of your tyres correctly and when it is necessary to change them.

What is the minimum tread depth for tyres?

The law stipulates the number of millimetres of tread depth above which a tyre change is mandatory - it is exactly 1.6 mm. In order to create overall standardisation, the specifications apply throughout Europe. By way of comparison, new tyres have a tread depth of 6 to 8 mm, depending on the manufacturer and type.

In principle, both tyre professionals and automobile associations agree that tyres with this tread depth have long since lost too much grip. Instead, the following tread depth values are recommended for your car tyres:

• Recommended minimum tread depth for summer tyres: 3 millimetres
• Recommended minimum tread depth for winter tyres and all-season tyres: 4 millimetres

This information is well above the minimum tread depth required by law.

Where is the minimum tread depth measured?

There are various ways for you to check the tread depth of the tyres you are currently using on your car. It is important to know that it is primarily the tread that is relevant for the measurement - i.e. the part of the tyre that is always in contact with the ground. The following options are available to you:

• Summer tyres: Use the one-euro coin to orientate yourself to the minimum tread depth recommended by associations and professionals. The gold-coloured edge of the coin is exactly 3 mm. If it disappears completely, the tyre tread is in order and allows you to drive safely.
• Winter tyres and all-season tyres: Use a two-euro coin to check whether the tread depth is still within the recommended range of over 4 mm, as the stepped edge is exactly this width.
• The wear indicators located directly on the tyres provide you with very reliable assistance. They are also known by the abbreviation TWI (Tread Wear Indicator). These are 6 clearly visible bars that are integrated into the main grooves of the tread in the tread area. If the bars and the tread blocks are on the same level, then the minimum tread depth has been reached or even fallen below.
• Another alternative is to use measuring devices to check relatively reliably whether the prescribed tread depth of 1.6 millimetres has already been reached or is still in the green zone.

You can obtain these from specialised dealers. The investment is manageable and worthwhile if you want to regularly check the minimum tread depth on several cars. In addition, the wear of the individual tyres on your vehicle can vary.

The tread depth must be measured regularly

Realistically speaking, every millimetre of the minimum tread depth on your tyres is important as soon as you drive your vehicle. As has been proven in various tests, too little tread on the tyres has a negative effect on driving safety in aquaplaning, snow and all other weather conditions on the road. These include:

• The braking distance: If the tread depth of your tyres decreases, you must inevitably expect a longer braking distance. According to the ADAC, for example, new winter tyres lose approx. 15% of their braking power on snow with a residual tread depth of 4 mm.
• Aquaplaning is similarly problematic with summer tyres: New tyres float much later than tyres with the recommended tread depth of 3 millimetres. Floating means that the grooves and sipes in the tyre tread can no longer displace enough water. It is obvious that the driving behaviour deteriorates further the closer you get to the prescribed minimum tread depth.

With winter tyres, this can have fatal consequences if you are travelling in regions with increased snowfall and icy conditions.

What happens if I drive with worn tyres?

If your summer tyres, winter tyres and all-weather tyres have reached or even fallen below the legal minimum tread depth , this not only affects your own safety when driving. You could face a fine of varying amounts, depending on the situation. If you are the vehicle owner, the amounts increase again.

Order new tyres in good time in our online shop

Whether all-season tyres, winter tyres or summer tyres, we have the right tyres for practically every type of vehicle, from cars and motorhomes to trucks.

In addition to the minimum tread depth, the age of the tyres also plays a role: replacement is recommended after 6 years at the latest, as the rubber compound not only suffers from abrasion, but also loses quality due to different weather conditions. The tyre age can be identified by the DOT number on the tyre sidewall. It consists of four digits that indicate the year and week of production of the tyre.