A slipper clutch is a specialized clutch with an integrated freewheel mechanism, developed for performance-oriented motorcycles to mitigate the effects of engine braking when riders decelerate. The main purpose of a slipper clutch is to prevent over-revving of the engine and rear-wheel hop (or clatter) under hard braking scenarios in a motor vehicle. Slipper clutches help by allowing the clutch to partially slip until the engine speed matches the speed of the vehicle, preventing the rear wheel from locking up.
The design of a slipper clutch consists of two bases, one with dog clutches and ramps with ball bearings, a splined hub, and clutch plates. In normal operation, the dog clutches mate, driving the transmission. When a back torque comes from the transmission, the splined hub slides up the bearing ramps, disconnecting from the clutch plates and allowing a limited slip between input and output. Slipper clutches eliminate the extra loading on the rear suspension, giving riders a more predictable ride and minimizing the risk of over-revving the engine during downshifts.
Slipper clutches can also prevent a catastrophic rear wheel lockup in case of engine seizure. They have been used to a lesser extent on automobiles, primarily those powered by motorcycle engines, and can also be found on racing remote control cars. Slipper clutches are mechanically complex and expensive, but they reduce wear and tear of transmission, less suspension movement, and increase rider safety.
