Well if you'd like to replace the tires on your SCX Nascar you might want to check out the new Super Tires #1601 which are made specifically for SCX Nascars. They are sold by Fantasy World Hobbies and Slot Car Corner, both are good friends of Slot Cars Blog. Slot Car Corner is the place I'd start because I happen to know Steve, who runs SCC, and he's a Nascar kinda guy so I'm guessing that he will have them in stock.