the frame of an in - line skate supports a wheel , allowing a skater to effectively slow down and stop , using an athletic stance that skiers on snow and ice skaters on ice use . the wheel has a hub , allowing a wheel to rotate around the axle vertically and at an inclination . the hub has axle roller bearings . the wheel includes friction band surfaces on the sides of the wheel . when rotating at an inclination the wheel &# 39 ; s friction surface contacts a friction surface , inside the wheel - well or an axle friction surface or a combination thereof to slow or brake the wheel . the wheel assembly includes self - aligning springs . individual parts can be technically designed to allow various model solutions that will satisfy the abilities of a beginner to an expert . the wheel assembly frame can be attached to an in - line skate , an in - line skateboard , a downhill in - line ski and a downhill in - line skateboard .