Bones Rough Riders All-Terrain Formula 80A Wheels The Bones Rough Riders All-Terrain 80A Wheels are made to keep you rolling smoothly when the pavement gets rough. Bones&'; All-Terrain Formula(TM) (ATF) uses a specially formulated soft urethane designed for rougher terrain, helping you maintain a quick, smooth roll even when road quality isn&';t ideal. With an 80A hardness, smooth surface, and CORE shape, Rough Riders are available in 56mm and 59mm sizes with multiple color options to fit your setup. Details Formula: All-Terrain Formula(TM) (ATF) Hardness: 80A Suggested Use: All Terrain Shape: CORE Wheel Core: Yes Surface: Smooth 56mm Size: 56mm diameter / 40mm width 59mm Size: 59mm diameter / 44mm width