header
 

What are the main components in a chain kit?

How to determine the size?

Front Sprocket

Rear Sprocket

Drive Chain

How to modify?

Front Sprocket

Rear Sprocket

What types available on the market?

Front Sprocket

Rear Sprocket

Drive Chain

Chain Connections

When to replace?

Rear and Front Sprockets

Drive Chain

How to maintain?

 

header

header

What are the main components in a chain kit?

Most motorbikes use a chain to transfer the engine power to the rear wheel.

The main components are the:

  • Front or drive sprocket
  • Rear or driven sprocket
  • Drive chain

Expert advice: It's recommended to replace all these parts together as a worn sprocket or a worn chain can spoil the new parts quicker.

Back to Top

How to determine the size?

Front Sprocket

The front sprocket is fitted to the drive shaft. The shape and size of the drive shaft is motorbike specific. One should always look for the same shape otherwise the new sprocket won't fit.

header A = Internal Teeth Number
B = Inner Diameter Min
C = Inner Diameter Max
D = Width
E = Hole Spacing

The size of the sprocket is determined by the number of teeth.

The other important spec is the pitch which is the length and distance between the teeth. The most common pitches are 420, 428, 520, 525, 530.

The pitch and the number of teeth are always shown on the sprocket, however if for some reason it is not visible, you can also count the number of teeth and take the pitch from the rear sprocket or the chain.

Expert advice: The pitch must be the same for the sprockets and the chain.

Back to Top
header
header

Rear Sprocket

The rear sprocket is on the rear wheel connected to the wheel hub. The fitting holes size and position are motorbike specific.

header A = PCD
B1, B2 = Bolt Hole Diameter
C = Inner Diameter

The size of the sprocket is determined by the number of teeth.

The other important spec is the pitch which is the length and distance between the teeth. The most common pitches are 420, 428, 520, 525, 530.

You will also find these numbers printed on the sprocket.

Back to Top

Drive Chain

The chain connects the 2 sprockets and transfers the power to the rear wheel.

The pitch, which is also printed on the side plates, refers to the distancce between the rollers.

The length is the number of chain links.

User specific chains are available for special needs (ie quad/ATV, trial, race etc).

Expert advice: To make sure that you buy the right length, it is recommended to count the number of teeth starting from the connection link.

Back to Top
header
header

How to modify?

Front Sprocket

Most manufacturer spend a lot of time on making sure that the motorbike has the right power. If you are satisfied with the current gear ratio, just buy the same sprockets and chain. This way you will know that it perfectly fits your motorbike and you will get the manufacturer specified acceleration and top speed.

Alternatively buying different sprockets are a cheap and simple solution to modify the gear ratio.

Always keep the pitch and the motorbike specific centre hole the same and only modify the number of teeth.

Lower teeth count will give you better acceleration and lower top speed, which is ideal for:

  • Travelling with passengers
  • City traffic
  • Uphill
  • Off road
  • Stunt bikes

More teeth will have:

  • Higher top speed
  • Better fuel consumption
  • More comfort on the motorway
  • Depending on the scale of the modification, worse acceleation

Expert advice: Only modify the front sprocket +/- 1-2 teeth to start off and test your motorbike afterwards. A front sprocket is relatively cheap (cca £10) and it gives you way more control. Beware if you fit a bigger front sprocket, your chain might need to be longer too. If you are unsure, buy a longer chain (again, the extra links will be cheap compared to buying another chain) and you can remove some unwanted links later to make it tight.

Back to Top

Rear Sprocket

The situation with the rear sprocket is completely the other way around than the front sprocket. Higher teeth count will give you better accelerationa and lower will increase your top speed.

However, please note that as the front sprocket has less teeth, increasing or reducing this number, will have much higher impact on the gear ratio than doing the same on the rear sprocket.

Expert advice: The best way to find the best gear ratio for your motorbike and your specific needs (ie commute, track), read some model specific forums where users share their experience. 

For more popular models conversion kits are available (ie 520 pitch to 525 pitch), but using this means that you must replace the whole chain kit.

Back to Top
header
header

What types available on the market?

Front sprockets

The main material for most front sprocket is high quality steel. This makes it durable and cheap and because the size is relatively small, the rotation mass is irrelevant. Since most of the time the front sprocket is not visible, the main characteristic of the sprocket is based on performance rather than appearance.

  • Standard
  • Self-Cleaning:
  • Special millings between the teeth, give some self-cleaning effect as dirt and oil can't stick to this surface as good. This will provide longer lifetime for not just the front sprocket, but the whole power line.
  • Rubber cushed
  • The center of sprocket is connected to the outer teeth with a flexible rubber cushed connection. This makes the transition smoother.
Back to Top

Rear Sprockets

The rear sprocket is bigger and visible, so more material types and colours are available. This gives you the opportunity to add some style to the motorbike.

As it is on the rear wheel the rotation mass could be important, therefore lightweight versions are available.

  • High quality steel
  • Durable and cheap
  • Lightweight (aluminium)
  • Less rotation mass, less durable
  • Dual (steel outer + aluminium center)
  • Lighter weight than steel with the same lifetime
  • Self-Cleaning
  • Special millings between the teeth, give some self-cleaning effect as dirt and oil can't stick to this surface as good. This will provide longer lifetime for not just the rear sprocket, but the whole power line.
These versions are mostly available in a rainbow of colours.
Back to Top
header
header

Drive Chains

The main material of the chain is high quality steel which can differ in colour.

  • Plain steel
  • Gold
  • Nickel
  • Colours: Red, Blue, Yellow, Orange, Green, Black

By the ring type:

  • Standard (Non O-Ring)
  • No sealing between the plates and the rollers. The dirt can get inside the rollers and lube can escape, so while it is cheaper, it has shorter lifetime. Only recommended for small or off-road bikes.
  • O-Ring
  • Circular cross-section seals preventing the lube from escaping, the dirt getting inside which provides longer lifetime, but more friction.
  • X-Ring
  • X shaped cross-section with 4 sealing points to reduce the friction and provide even longer lifetime.
  • WX-Ring
  • High-end chains with W shaped cross-section and 6 sealing points with longest lifetime and very low friction.
Back to Top

Chain Connections

  • Spring link
  • The easiest to fit as it doesn't require any special tool.
  • Rivet link
  • Very easy to fit with a chain riveter.
  • Endless
  • No connection link (weak link) and has the longest lifetime, however fitting could be more difficult. Mostly recommended for high performance motorbikes.

Some chains contain spring and rivet link as well for you to decide which option you prefer.

Expert advice: Spring and rivet links are available to purchase separately. Always use suitable quality tools as an incorrectly fitted chain can be dangerous.

Back to Top
header
header

When to replace?

Front and Rear sprockets

Unless you are not satisfied with the current gear ratio, sprockets need to be replaced when the teeth looks sharper.

Expert advice: It's recommended to replace the sprockets and the chain together as a worn part can reduce the lifetime of the new parts.

Back to Top

Drive Chain

When the chain gets loose or noisy this means that it's time to replace your chain.

Expert advice: For longer lifetime check your chain tension regularly and if needed adjust it. The owners manual will provide you with information on how to do it and what tension is required.

Back to Top
header
header

How to maintain?

A properly fitted and maintained chain kit will give you loads of miles to ride. However even the most expensive chain kit will have dramatically shorter lifetime if not fitted the right way and maintenance is missed.

When fitting: Make sure that the tension is set to the right level. Check the chain alignment (for the best result, use laser chain alignment tools).

Every 300 miles (or more often in extreme conditions), use a good quality chain lube. Make sure that it's specifically made for chains.

Every 2000 miles give it a full service with chain cleaner, brush and lube. Again, use special chain products as strong chemicals (ie brake cleaners) can damage the seals.

Don't use jet wash to clean the chain as this can remove the lube from between the rollers (this is inserted when manufactured and can't be replaced).

An automatic chain oiler system can be a very convenient way to maintain your chain as once fitted you will only need to re-fill the oil tank.

Expert advice: When using lube or cleaning the chain, always protect your brake components and rear tyre. Some chain lube on these parts can be very dangerous.

Back to Top

< Back