Auto Bild 2019: Used Summer Tire Test

Shortly before announcing the results of its traditional grand-scale winter tire test, the German publication Auto Bild decided to present to its readers an article containing the results of a summer tire test. However, this was not just another test — it involved tires with different degrees of wear.

It was as if the German experts decided to answer the challenge of one certain French tire maker to use its tires until they are worn down to the minimum legal tread depth of 1.6 mm.
The results of the used tire test were nothing to be happy about — no matter what the tire makers may claim, the used tires significantly cut down the level of road safety.

As is known, water on the road surface is a problem for motorists that must not be underestimated by any means. When driving in the rain, a hydroplaning effect may occur that can lead to the driver completely losing control of the vehicle. How great is the danger of driving on wet pavement on tires with various degrees of wear was the subject matter of the test conducted by Auto Bild.
The test involved 225/45 R17 premium-class tires Michelin Primacy 4, Goodyear Eagle F1 Asymmetric 3, and Continental PremiumContact 6 with a remaining tread depth of 1.6 mm, 3 mm, 5mm, and in a brand new condition.

Test Results

Test results

The program only included three disciplines, but that was enough to show how dangerous used tires are. For example, testing the braking performance from 120 km/h on wet pavement showed that tires with a remaining tread depth 1.6 mm needed a braking distance almost three times as long than the brand new ones. And this with the water layer only 1 mm deep!

While braking from 80 km/h, the difference in the results was not so drastic but the 10-meter gap was still there virtually with every model on test.

The «floating» of tires at highway speeds could not be fully stopped even by the vehicles’ smart electronic systems, such as ABS and ESP. Tires with a remaining tread depth of 1.6 mm can start slipping already at a speed of 63 km/h, while brand new tires can put off this moment up to at least 80 km/h.

Test Conclusion

Summing up the results of its work, the test group emphasized that when it comes to wet pavement, the largest safety margin can only be ensured by new tires. The safety margin provided by the tires with a remaining tread depth down to 3 mm is conditionally acceptable but the minimum legal tread depth of 1.6 mm is downright dangerous.

We will remind you at this point that similar tests have been conducted in 2019 by ADAC experts, the difference being that their test program only involved winter tires. Nevertheless, based on the results of their tests, the Auto Build experts came to the exact same conclusion: if you care about safe driving, you must have you tires replaced well before the tread depth wears down to 3 mm.