One of our readers noticed that his classic on flat and tight, asphalted road had been making an extremely annoying, but above all strange, thumping sound for weeks at a certain speed. He presented the problem to his tire supplier who, after inspecting the rubber product, noted that the rear tires were 'cupped'.
New tires were fitted and now the sound is gone. He recently wondered what "cupping" was. A 'cupped' tire has a different wear pattern and can often be found on a front-wheel drive automobile. The band has a saw-tooth profile, that is to say, the profile blocks wear obliquely, so that there is a mutual difference in height. That is not only heard, but also felt. Stroke over the profile and you will feel 'sharp' edges in one direction. The cause must be found in long-term driving with a tire pressure that is too low, alignment of the chassis and the exact position of the wheel in relation to the road surface. For the sake of good steering behavior (and therefore handling), the rear wheels of a front-wheel drive are a bit inward. So accost. The front wheels, incidentally, are on track because they pull themselves under the force of acceleration. The make and type of tire, as well as the driving conditions, the way you steer and brake, also have an influence on the abnormal wear pattern. The solution, exchanging the front and rear tires once per 10.000 kilometer and keeping a close eye on the tension!