The Toyo Proxes RA-1, a DOT-approved competition tire designed specifically for improved touring racing and autocross, features all the high-tech components to provide you with an uncommon competitive advantage. It's a proven winner.From its aggressive directional tread design to its steel wire-reinforced sidewalls, the purpose is clear-- to maintain your winning edge. At its full tread depth (8/32 inch) the RA-1 provides wet traction, but shave it to 4/32 inch and hang on as your dry lap times drop!