How does this even happen to a tire???
German tires are made with Nylon. This is an unusual plastic in that it does not expand when heated. It actually contracts. This makes the tire hold the rim better, and keeps the belts and cords in place.
Look on the side wall to make sure all your tires come from the same country.

Wow they must be a hard compound. My Conti SC3's made in Germany on my CLK are just about finished at 26K Kilometres.







