It happens to most of us, when we unknowingly downshift a gear more than we should have, and we hear that gnawing, disgruntling noise from the engine. As if the engine wants to tell you, ” I am disappointed in you, mate.” If it has happened with you, read along!
What does a clutch do?
The job of a clutch is to transmit the engine power to the gear-box. Then power is transmitted from the gear-box to the rear wheel via drivetrain. But when the driver closes the throttle the engine stops transmitting to the rear wheel and now, the wheel controls the movement of the pistons, through the drivetrain.
What happens when you do excessive downshifting?
When we shift a gear or two lower than that required, the speed of wheel exceeds that of the engine. Meaning, the rear wheel wants to move forward, but the engine speed suddenly drops. There are two forces acting in opposite directions.
The resulting torque creates immense pressure on the bike’s swingarm, chain, rear sprocket and rear wheel. This may also result in loss of traction at the rear wheel causing the bike to skid.
This is where slipper clutch comes in.
What a slipper clutch does is, when ever you do aggressive downshifting, it disengages the engine from the drivetrain. With the clutch disengaged, engine is safe. It only re-engages when the speed of engine and the wheel are in compatible range. Very simple, yet so complicated!
Advantages and disadvantages
Most important advantage is that it increases safety by preventing disastrous rear-wheel lock-up. It also prevents wear and tear on the transmission. The rider doesn’t have to concentrate on clutch operation so he can pay attention to other details.
Main disadvantages are it is expensive and mechanically very complex.
Also some riders may argue, engine braking if done right is a very useful way to use downshifting to slow your bike. Engine braking is particularly useful while riding down the slope where using brake is a bit risky. I will tell more about engine braking in a new blog. Till then, goodbye!