Most motorcycles and mopeds use a front sprocket, rear sprocket (also called a chainring), and chain to transfer engine power to the rear wheel. These three parts together are referred to as a chain kit, and it is usually recommended to replace all components at the same time.

On a motorcycle or motocross bike, the front sprocket sits on the gearbox output shaft. On a moped, it is connected to the rear pulley (which in turn is driven by the V-belt).
This front sprocket drives the chain, which acts as the link between the engine and the rear wheel by turning the rear sprocket.
The rear sprocket is mounted to the rear wheel hub and ultimately turns the wheel so the bike moves forward.

There are different chain types that vary in size and length as well as intended use. There are basic chains or reinforced versions. Others are equipped with sealing rings (O-ring, X-ring, or U-ring), which makes them quieter and longer-lasting. For off-road use, there are special versions with specific surface finishes to withstand the demands of riding on rough terrain.

Front sprockets and rear sprockets are available in steel or aluminum (lighter, but less durable). For off-road use, self-cleaning versions are also available, with special cutouts between the teeth that help carry dirt away.

Choosing the right gearing

Each element of the chain kit should be selected carefully. Depending on engine output and intended use, different criteria can become important (see the previous chapter on off-road use).

Chain pitch is a key criterion: the more powerful the engine and the higher the torque, the larger the pitch.

An example: A classic moped uses a chain with a 415 pitch. An 85cc motocross bike, on the other hand, uses a 428 pitch, which is better suited to its output. A 1000cc sport bike uses a 530 pitch.

Choosing the right gearing has a direct impact on top speed and how responsive the bike feels. But caution: a weak engine cannot be run with gear ratio that is too tall. Except with very extensive engine tuning, it is best not to deviate too far from the manufacturer recommendations. It is also worth keeping in mind that with a larger change, a longer or shorter chain may be required (chain adjusters have their limits).

An example: The engine has been tuned with a higher-displacement cylinder. There is now significantly more torque and the goal is a bit more top-end speed. This can be done by fitting a larger front sprocket or a smaller rear sprocket. If a more direct response when exiting corners is preferred, a larger rear sprocket or a smaller front sprocket is used.

WARNING! One tooth more or less on the front sprocket has a much bigger effect than on the rear sprocket. It is generally said that one tooth on the front sprocket is roughly equivalent to three teeth on the rear sprocket.

Maintenance tips

Chain maintenance is very easy, but it needs to be done very regularly. Brushes and special products are available to clean the chain carefully and then grease it. The more thorough the work, the longer the chain kit lasts.

It should be noted that a new chain stretches a bit more during initial use than it does afterward. Chain tension should therefore be checked after the first ride and then regularly, to avoid the chain coming off or damage to the swingarm or other components (such as the shift lever on some models).

For off-road riders (motocross, enduro), chain care should be done after every ride, using a special off-road chain grease.

It should also be noted that some parts are in direct contact with the chain and their condition also needs to be monitored: the chain guide must a) be present and b) be in good condition so the chain does not come off. The swingarm slider protects the swingarm from friction caused by the chain.

Chain, front sprocket, and rear sprocket in our shop

In our online shop, complete chain kits are available for motorcycles, motocross bikes, and mopeds with chain drive, as well as all individual parts, to offer a very large selection.

Products in OEM quality are available, as well as reinforced versions from well-known brands such as AFAM, Iris, Moto Master, Prox, MotoForce, Stage6 or Voca Racing, Doppler, etc.

We try to always stock items for the most popular models on the market at the best prices and with short delivery times. Owners of Derbi Senda, Rieju MRT, Beta RR, Sherco SM/SE, Yamaha YZ / DT, KTM EXC / SX, Honda CRF ... etc. will find what they need.