Toyo Mustang Proxes R888R Competition Summer Tire TOYO 104430 (315 Toyo Proxes R888R Track Day Tire Tire Review: Toyo Proxes R888R YouTube Toyo Proxes R888R Tire 315 30ZR20 101Y SL. The Proxes R888R DOT competition tire* is an evolution of the race winning Proxes R888, delivering even faster lap times and better dry handling. The credit goes to a new tread design and an improved contact patch that puts more rubber on the track. Racers will also appreciate the predictable handling and how quickly the Proxes R888R reaches optimal operating temperature.*Caution: Recommended for competition events only. Large Tread Blocks on Outside Tread Maximizes lateral grip for improved cornering. Wide Center Rib Improves directional stability and precise steering response. Water Evacuation Channel Assists with wet traction. High Grip Race Compound Reaches optimal operating temperature quickly and provides consistent performance. Improves grip for excellent cornering performance. Optimized Contact Patch Improves dry traction in braking, acceleration, and cornering.