[joelster]

I've talked to plenty of guys who swear you can run "tire x" down to the cords, but from my own personal experience tires will start to fall off after 7 or 8 events. Even if you don't street drive them at all. They can only be heated/cooled so many times before they don't work as good as they used to. I sold my last set of 660's for $100. They still had 4/32nds left but I could tell they weren't as good and I had some important races coming up and a fresh set in the garage.