fatbillybob

We all know that the best a race "slick" is in the first 5-10 laps. Every heat cycle degrades performance. We know that a hi-performance street tire can't give the absoulte performance but what it can give it will for many heat cycles. ..true? Somewhere DOT race rubber falls in the middle. So the question is how many times can you heat cycle a racing slick to the point where it is no better than a street tire...if that is even possible? How many times can you heat cycle a racing slick so it is no better than DOT race rubber? How many times can you heat clcle a dot race rubber to the point where it is no better than a street tire?

Larry Herman

I know that Norm Goldrich has talked a lot about race tires, and how quickly they can go away for him. His Dunlops degrade with each heat cycle, and he has stated that they are many seconds slower after the third cycle. Personally, I have found that the Pirellis that I used were noticably slower after 8 heat cycles, and the difference was pronounced when I just put on new rear tires. There was quite a bit of understeer due to the heat cycled front tires. I have also had Dunlop SSRs "go off" on me. At VIR, after the 8th or 9th cycle, the rears just started loosing grip. It was oversteer city after that.

One important thing that most people do not take into consideration is how hard they drive their tires, and how much that affects tire life. My Pirelli P Zeros were worn out after 8 cycles, as confirmed by Bob Woodman tires, yet other people who run them feel like they last a long time, 15 to 20 heat cycles. That doesn't make any sense until you factor in that I am 3 to 4 seconds a lap faster than they are. I asked Leh Keen how long the tires lasted on his cup car, and he told me...45 minutes

A good rule of thumb is that the softer the tire, the faster it will go off; the harder you drive it, the faster it will go off. How much and how far would be a hard thing to quantify. Once again, Norm has said that his Dunlops are really fast, but go off very quickly. He has run the Pirellis as well, and has found them to be slower, but seemed to hold their performance longer. Maybe with more input you can get more of a general answer to your question.

Dbltime

I would think that since slicks start out at 10 on the grip scale and DOT's are 7.5 on the grip scale that after X heat cycles the slicks would still provide more grip. I have no experience with slicks so this theory scores "0" on the research scale.

pig4bill

How many heat cycles until slicks are no better than street tires? In my experience, forever, until all the rubber has worn off and they won't hold air.

38D

I ran goodyear G19 slicks last year, and they lasted about 4 DE days (and then they were down to the wear bars...and my car was only about 2000 lbs). They were definitely faster when new (I would estimate 3+ seconds at Watkins Glen). I found no need to scrub them in, and just went a bit slower for 2-3 laps, then cranked it up. My experience is that a slick with 10+ heat cycles is not that different than a used hoosier (i.e. they fall off more dramatically).