• A centrifugal clutch is a clutch that uses centrifugal force to connect two concentric shafts, with the driving shaft nested inside the driven shaft.
• It consists of number of shoe on the inside of a rim of pulley. The outer surface of pulley is covered with friction material.
• These shoes move radially in guides.
• As the speed of the shaft increase, the centrifugal force on the shoes increases.
A freewheel mechanism on a bicycle allows the rear wheel to turn faster than the pedals. If there is no freewheel on a bicycle, a simple ride could be exhausting, because one could never stop pumping the pedals. And going downhill would be downright dangerous, because the pedals would turn on their own, faster than one could keep up with them.