If you have to replace it, you might want to consider the Shinko 777. Stock size, <$90 at several online stores with shipping included, and mounts and balances easily. I'm on track for over 10K miles from mine after only getting 6K (and it was bald) out of my rear Bridgestone BT45. And, I think it sticks/handles as well as the BT45 even when leaned to extremes. Couple that with a PR3 up front, and you've got a very confidence inspiring combination.