R compound avail in Michelin Pilot SPORT CUP in size 265-30-19 for the rear. so far, they're the only one with rear tire close enough for us to use. Tirerack says these 80 rated tires are strong enough to drive to the track. They don't recommend hoosiers or kuhmo for highway use. And since we can't figure out a way for a hitch, that only leaves trailering the xfire to an event...which gets to be expensive (buying a trailer). Fear not, the new vette will have 19" in the rear. so the tire makers WILL have to come up with new 19 inchers. although the new C6 will have much wider tires.