I have been running a set of unshaved RA-1s on the street (3k miles), 8 autoX and 2 HPDEs. They are now just starting to wear (pretty evenly) down to the good range (2 strips showing, most of the other tread gone). Not sure, but at the last few events the tires seemed to have about the same amount of grip even though the tread looks better. I was under the impression that RA-1s don't really stiffen as a result of heat cycles, what is your experience with this?

 

We've posted about RA1's already, and we're in pretty much the same situation. My experience similar.

I understood that no tire is going to be as sticky as when their fresh. When my tires were new they had a lot more grip, even with the wet tread blocks and not warmed up. Now to get around say 80%-90% of the grip they have to get warmed up. When cold on autocross they are still probably a little better than new SO2's. IMO, they do recover from overheating well. My SO2's were never the same after I overheated them, while the RA1's will come back again and again. It still sticks in my head that the tire shop (which caters to club racers) that were sourcing the RA1's to me, asked if I was willing to wait a week because he didn't have the correct sizes that were the same YEAR of manufacture. He said that the grip would be mismatched, just because of age.

I've decided to take the next step and get some street tires/rims and compromise track/autocross (shaved RA1's) and rims. Give up great early life rain tire/street use RA1's for better dry grip and eliminate RA1 tread block squirm.