Gears make the final drive and just how then do they work on a motorcycle? Gears are used in heaps of mechanical devices not just motorcycles. You can observe “gears” in just about everything that's got spinning parts even your old VCR even the family's inherited wind up grandfather and pendulum clocks contain plenty of gears, especially if they have bells or chimes. Take a look at the power/gas metre of your house; it too has gears which you've probably noticed by looking into its see through window.  Car engines and motorcycle transmissions contain lots of gears.

Your motorcycle's engine can create an enormous amount of power, which must be delivered to the wheels of the vehicle in a controllable way. The motorcycle transmission delivers power to the rear wheel through a series of structures that include the gears or gear set (usually one gear down and 5 up), the clutch and the drive system. You need the clutch because your engine is spinning all the time, yet your motorcycle wheels don't. Therefore, in order for the bike to stop without killing the engine, the wheels need to be disconnected from the engine somehow. The clutch allows us to smoothly engage a spinning engine to a non-spinning transmission by controlling the slippage between them.

The job of a clutch is to engage and disengage power from the engine crankshaft to the transmission. Without the clutch, the only way to stop the wheels from turning would be to turn off the engine -- an unrealistic solution in any kind of motorized vehicle. The clutch is a series of spring-loaded plates that, when pressed together; connect the transmission to the crankshaft. When a rider wants to shift gears, the clutch is used to disconnect the transmission from the crankshaft. Once the new gear is selected, the clutch is released to re-establish the connection. Have a look at our earlier article on the clutch.

A gear set is exactly as it states: a set of gears that enable a rider to move from a complete stop to a cruising speed. Transmissions on motorcycles typically have anywhere from four to six gears, although small bikes may have as few as two. The gears are engaged by shifting a lever, which moves shifting forks inside the transmission.

There are three basic ways to transmit engine power to the rear wheel of a motorcycle, either by a chain, belt or shaft—these are referred to as your ‘final drive” the thing that finally gets you driving/moving. Chain final-drive systems are undoubtedly the most common. In this system, a sprocket mounted to the output shaft (i.e., the shaft in the transmission) and is connected to a sprocket attached to the rear wheel of the motorcycle by a metal chain. When the transmission turns the smaller front sprocket, power is transmitted along the chain to the larger rear sprocket, which then turns the rear wheel. This system does require the most maintenance yet is the least expensive by comparison to the others in case of replacement. The chain needs to be lubricated and adjusted, plus the chain stretches and the sprockets wear, requiring eventual replacements. Again, not a costly final drive.