D21 Heat Cycling

[Matt49]

About how many heat cycles are you guys getting out of your D21s before they start to get bad? We get about 6 heat cycles and then after that they are only good for short runs regardless of track conditions. They go away after about 4 laps it seems. Have others had this same experience?

[MasterSbilt_Racer]

About how many heat cycles are you guys getting out of your D21s before they start to get bad? We get about 6 heat cycles and then after that they are only good for short runs regardless of track conditions. They go away after about 4 laps it seems. Have others had this same experience?

I have noticed the SPEC 21 doing that on some surfaces. I never had that problem with the old 21s when they were an economy tire compound.

[gadirtracer]

6 cycles in a SPEC D21 on a Late, WOW. Sounds like the tire is too hard for track conditions. After qualifing and a 30 lapper and they are gone. On the lower classes, I'd put a new RR D21 on after 2 nights, and the car would pick up, although, tire would only be 1/2 worn.