[thstone]

20-25 heat cycles is about the useful life of the R888 here in SoCal. I replaced my set of R888's at 27 heat cycles and there wasn't much grip left in them at that point. When heat cycled out, the tire looses grip and starts to feel greasy and slide around rather than sticking solidly like when new. The tires typically still have a good amount of tread left even though they are heat cycled out and some people use them for practice and testing but use new tires for events/sessions that matter. As long as it feels good on the track, you are fine to drive it to the cord.