A slipper clutch (also known as a back-torque limiter) is a specialized clutch with an integrated freewheel mechanism, developed for performance oriented motorcycles to mitigate the effects of engine braking when riders decelerate.
Theory of Operation:
The 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.This type of clutch is designed to partially disengage or “slip” when the rear wheel tries to drive the engine faster than it would run under its own power. The engine braking forces in conventional clutches will normally be transmitted back along the drive chain causing the rear wheel to hop, chatter or lose traction. This is especially noted on larger displacement four-stroke engines, which have greater engine braking than their two-stroke or smaller displacement counterparts. Slipper clutches eliminate this extra loading on the rear suspension giving riders a more predictable ride and minimize the risk of over-revving the engine during downshifts. Slipper clutches can also prevent a catastrophic rear wheel lockup in case of engine seizure. Generally, the amount of force needed to disengage the clutch is adjustable to suit the application.