After a trip to the Black Forest, my front tyre on the flanks with a strong sawtooth profile completely went off. The tyres are Bridgestone BTO20. The rear tyre looks fine. The motorcycle BJ 2007 ran 4000 km (after the trip of approx. 600 km) and had had a normal profile abrasion before, i.e. 70% is still on it. Since the phenomenon occurred on a single day I am a bit perplexed. Do you know the problem?