- Jan 10, 2010
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Your chain is a key element of your bike's transmission, being the essential link that connects the front part of your drivetrain (the pedals, cranks and chainrings/sprocket) to the rear (cassette/sprocket and rear hub). It's through the chain that pedal power is converted into forward movement, so it's essential to buy the right one and to keep it maintained.
Modern bike chains are properly called 'roller chains', and consist of short cylindrical rollers held together by side links. The gaps between the rollers mesh with the teeth on a sprocket or chainring, to drive the transmission when turned.
Most bike chains are made of alloy steel for strength but some performance models may feature high-end alloy parts or hollow pins/side plates to save weight.
The type of chain you need will depend on the type of bike you are riding. A number of different chain widths are available, to suit specific bike types such as BMX, or to fit different road and MTB drivetrains (e.g. an 11-speed cassette requires a different chain to a 9-speed one – the chain must be thinner in order to fit into the narrower spaces between the sprockets.
Whatever bike you ride, chain maintenance is key. Chains will wear and stretch over time, and a worn chain will damage the teeth on your chainrings or sprocket. It's important to keep your chain clean and lubricated to minimise wear, and to regularly check chain length so it can be replaced when necessary.
When replacing your road or mountain bike chain you need to get one that matches the number of gears in your drivetrain.
The amount of sprockets on your rear cassette – 9, 10 or 11 is crucial. Because the distances between the sprockets vary on different 'speed' cassettes (e.g. the gap will be wider on a 9-speed block than on an 11-speed), you need a chain that fits. A chain for an 11-speed transmission will be narrower than one for a 9-speed, etc.
Generally chains and cassettes from different manufacturers will be compatible with each other, although Shimano and SRAM chains will not work very well with Campagnolo cassettes, and vice-versa.
It is also worth noting that some chains (e.g. Shimano) require special rivets to rejoin them once they have been split, and the old rivets cannot be used again. SRAM chains use a special 'Powerlink 'that can be split and rejoined without the need for a special chain tool, making them a popular choice even on non-SRAM transmissions.
What is Chain Stretch
Cyclists often speak of chain "stretch", as if the side plates of an old chain were pulled out of shape by the repeated stresses of pedaling. This is not actually how chains elongate. The major cause of chain "stretch" is wearing away of the metal where the link pin rotates inside of the bushing (or the "bushing" part of the inside plate) as the chain links flex and straighten as the chain goes onto and off of the sprockets. If you take apart an old, worn-out chain, you can easily see the little notches worn into the sides of the link pins by the inside edges of the bushings.
All chains have a limited lifespan. Every time a link of a chain drops into the valley created between the teeth on a cassette, sprocket or chainring, two metal surfaces rub together. Add in the grinding paste that a transmission attracts and multiply by the hundreds of times this happens every time you turn the pedals, and you have a recipe for wear and tear.
When do I Need a New Chain?
As chains wear out they tend to stretch, eventually starting to skip over the teeth on the sprocket when under load, instead of meshing with them as they should.
Once this starts to happen it is time for a chain replacement (and perhaps a new cassette and chainrings too, if the wear is considerable). However you can act earlier by using a chain measuring device to determine if your chain is beginning to wear – catch it quickly and you only need a new chain.
An alternative, but less accurate, method is to measure the length of 12 links, which on a new chain should be exactly 12”. When 12 links of an old chain measures 12 and 1/8” or less, you can get away with a new chain only. Any more than that however and you are going to have to buy a new cassette and possibly chainrings as well.
Modern bike chains are properly called 'roller chains', and consist of short cylindrical rollers held together by side links. The gaps between the rollers mesh with the teeth on a sprocket or chainring, to drive the transmission when turned.
Most bike chains are made of alloy steel for strength but some performance models may feature high-end alloy parts or hollow pins/side plates to save weight.
The type of chain you need will depend on the type of bike you are riding. A number of different chain widths are available, to suit specific bike types such as BMX, or to fit different road and MTB drivetrains (e.g. an 11-speed cassette requires a different chain to a 9-speed one – the chain must be thinner in order to fit into the narrower spaces between the sprockets.
Whatever bike you ride, chain maintenance is key. Chains will wear and stretch over time, and a worn chain will damage the teeth on your chainrings or sprocket. It's important to keep your chain clean and lubricated to minimise wear, and to regularly check chain length so it can be replaced when necessary.
When replacing your road or mountain bike chain you need to get one that matches the number of gears in your drivetrain.
The amount of sprockets on your rear cassette – 9, 10 or 11 is crucial. Because the distances between the sprockets vary on different 'speed' cassettes (e.g. the gap will be wider on a 9-speed block than on an 11-speed), you need a chain that fits. A chain for an 11-speed transmission will be narrower than one for a 9-speed, etc.
Generally chains and cassettes from different manufacturers will be compatible with each other, although Shimano and SRAM chains will not work very well with Campagnolo cassettes, and vice-versa.
It is also worth noting that some chains (e.g. Shimano) require special rivets to rejoin them once they have been split, and the old rivets cannot be used again. SRAM chains use a special 'Powerlink 'that can be split and rejoined without the need for a special chain tool, making them a popular choice even on non-SRAM transmissions.
What is Chain Stretch
Cyclists often speak of chain "stretch", as if the side plates of an old chain were pulled out of shape by the repeated stresses of pedaling. This is not actually how chains elongate. The major cause of chain "stretch" is wearing away of the metal where the link pin rotates inside of the bushing (or the "bushing" part of the inside plate) as the chain links flex and straighten as the chain goes onto and off of the sprockets. If you take apart an old, worn-out chain, you can easily see the little notches worn into the sides of the link pins by the inside edges of the bushings.
All chains have a limited lifespan. Every time a link of a chain drops into the valley created between the teeth on a cassette, sprocket or chainring, two metal surfaces rub together. Add in the grinding paste that a transmission attracts and multiply by the hundreds of times this happens every time you turn the pedals, and you have a recipe for wear and tear.
When do I Need a New Chain?
As chains wear out they tend to stretch, eventually starting to skip over the teeth on the sprocket when under load, instead of meshing with them as they should.
Once this starts to happen it is time for a chain replacement (and perhaps a new cassette and chainrings too, if the wear is considerable). However you can act earlier by using a chain measuring device to determine if your chain is beginning to wear – catch it quickly and you only need a new chain.
An alternative, but less accurate, method is to measure the length of 12 links, which on a new chain should be exactly 12”. When 12 links of an old chain measures 12 and 1/8” or less, you can get away with a new chain only. Any more than that however and you are going to have to buy a new cassette and possibly chainrings as well.
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