Free-wheeling has the task of preventing the frictional effect of a connection in one direction of rotation.


In roller free-wheeling, rollers are pressed by springs into a narrowing gap between the inner and outer rings in one direction of rotation. If the inner ring drives the outer ring in the direction of the spring force, the rollers are jammed and a non-positive connection is created. When driven by the outer ring, this connection is cancelled.
Free-wheeling is used in the guide wheel of the torque converter and in the electric starter to protect against overspeeding. It became famous (or infamous) in two-stroke vintage cars, because it switched off the  engine brake while going downhill, thus protecting the unlubricated engine from destruction.