webweaver

The OEM Cup2s on my GT4 lasted 15 autocross events for a total of 158 runs (with each run anywhere between 34 to 72 seconds, and 7 to 12 minutes between runs). In the last autocross on the tires (12 runs), the car was sliding everywhere, and I got it into spins even with warm tires. So I'd say as soon as you get close to 150 runs, even when there's still a lot of tread left on tires and they might work fine on the road, it is time to change them.

I just installed RE-71Rs on the car and had an autocross event this past Sunday with 15 runs in total. Based on my experience with these tires on other cars, they last about the same number of runs.