Just like a normal clutch, that engages the engine with the final drive system, the slipper clutch does the same. In addition though, it offers certain benefits which a normal clutch cannot offer, and as a result it is more suited for more demanding racing conditions. So how is it different and what benefits does it offer, we have a look.
How is a slipper clutch different from a normal clutch?
A normal clutch provides an ON / OFF arrangement between the engine and final transmission. That means that you can either connect the engine to the rear wheel or disconnect it completely. There’s no room for slipping, however, it’s not the case with slipper clutch and it slips in case the speed of the engine and tyre does not match.
Why is a slipper clutch needed and what benefits does it offer?
A slipper clutch is needed because demanding race scenarios require aggressive downshifts and it’s not possible to apply brakes and then downshifts, as it would cause significant loss of time. Therefore, an agressive downshift is needed that would bring the bike in the right power band whithout any loss of momentum. An aggressive downshift in case of a normal clutch, results in wheel bouncing and loss of traction which is very dangerous and can put the rider in life-threatening circumstances.
A slipper clutch on the other hand allows some amount of slippage in case of aggressive downshifts and does not require you to match the speed of the engine and the rear wheel. The slippage prevents the wheel from bounding and preventing the loss of traction.
How does it work?
In case of engine braking (aggressive downshifts) the engine RPMs rise suddenly and the role of engine and rear wheel is reversed. The rear wheel tries to drive the engine quicker in order to match the road speed and engine speed. This puts the drive train under strain and generates back torque. This manifests itself in the form of squeal noise as the tire skids and tends to lock and as a result bounces. This happens due to the reason that clutch is unable to disengage on its own in this scenario.
However, the slipper clutch prevents this scenario by allowing freewheeling to certain extent in one direction by modulating the pressure between the friction plates. As the engine RPMs rise due to aggressive downshifts, it gets into slipper mode and pressure force reduces and thereby preventing the drive torque transmission to the wheel and preventing back torque.