Atom Wheels Atom Road Hog Wheels – Atom Road Hog Outdoor Roller Derby Skate Wheels Size 8-pack : Atom Road Hog Wheels – Atom Road Hog Outdoor Roller Derby Skate Wheels – A true outdoor speed wheel, the brand new 78A Road Hog is bright yellow with a black core. Think monster trucks and MAX speed for outdoor use!! 66mmx38mm. – Perfect for: Sidewalk/Boardwalk – Asphalt – Cement