If your shock is set up too hard it will chew the rear tyre up really badly, the same if theres too much weight over the rear tyre, also if the seal is failing (like mine
) it will have the same effect, I did the CSS at cadwell and wasnt riding anywhere near the speed I wanted to (loadsa slow riders on unpredictable lines so couldnt pass - 8ft CSS rule) and my rear was tearing up on a damp track!
PS the CSS technician lowered our tyre pressures to 30/32 on the day - maybe your tyres are overheating?
[Edited on 16-6-2003 by DJTera]