X8 Series Rear Wheel - Complete Wheel w/ Core Wheels are 12 3/8" in diameter (12 3/4" including treads) NOTE: Specify wheel mount side (from behind caddy) to ensure correct spoke curve and tread pattern. When mounted correctly, the "Arrow" tread pattern faces forward on both right and left side rear wheels of the X8, and the spoke curvature matches that of the front wheel.