A chain is the beating heart of your bicycle, without it you cannot drive your bike forward.
Sometimes you will need to know how to replace a bike chain which we explain in 8 simple steps. The main reasons for replacing bike chain include that the chain is worn, rusty and stiff, missing or just not the chain that you want.
Reasons for replacing bike chain
The chain is worn
When the rollers on the chain wear out, they can give the appearance of the chain being stretched. It can no longer sit on the cogs properly. A simple way to measure how much wear is on the chain is to use a chain measuring tool. However, as the chain is wearing, so are the teeth on the chainset, the rear cogs and the jockey wheels.
The chain wears the most quickly as it is constantly in contact with the rest of the transmission, so if it is only slightly worn, you can just change that. If it is more than 0.5% worn then you may well need to change other components. The only way to be really sure is by test riding.
The chain is rusty and stiff
If you have had to store your bike in damp conditions without using it for a long time, then the chain is one of the components that will really suffer. The chain is made of over eleven hundred tiny moving parts. If just two of those parts can no longer move independently then the whole transmission is affected. If it is really rusty then measuring it for wear will be impossible, in this case it’s best to just fit a new chain and give it a test ride.
The chain is missing
Sometimes the chain breaks, spins off and is lost forever. If this is the case you will need to fit a new chain. You will also need to test ride your bike afterwards to make sure that the new chain meshes well with the cogs and jockey wheels.
The chain is no longer the one that you want
You may want to change your chain for performance or aesthetic reasons. Maybe you would like a lighter chain or a different coloured one.
Process of replacing bike chain
If you currently have a chain on your bike then remove it. We have a handy YouTube video to help you with this as well as a step by step guide on how to remove a bike chain and how to fix a broken bike chain.
Getting the correct chain length
Your new chain will probably be too long for your bike, so you will need to make it the correct length before replacing bike chain. You can measure it against your old chain. To do this, first lay your chains, new and old, along a bench and line them up. Start with the rollers at the end until you get to the last pair of outer plates.
Non- Shimano™ chains– Remove the spare links from your new chain, remembering that you won’t need the outer plates on your replacement chain as these will be part of the joining link.
Shimano™ chains with a pin link– Remove the spare links from your new chain leaving a pair of outer plates at the end so that you can push the pin through.
If your chain is missing, or is very stiff and rusty, it will not be possible to use your old chain as a guide so you will have to assess the correct length.
Replacing bike chain in 8 simple steps
- Move the gear shifters so that they put the derailleur on the smallest cogs front and rear.
2. Feed the chain onto the bike. If you have a front derailleur, make sure that you pass it through this before moving onto the next step.
3. Hold the end in your right hand so that it is between the rear and front cogs.
4. Now pull on the rest of the chain in your left hand so that there is a small amount of tension on the chain and the rear derailleur is parallel to the floor.
5. When you go to shorten the chain, make sure you use the tool to push the rivet out so that it leaves the correct end for your joining link.
6. Finally check that the chain isn’t too short by changing gear so that you are running the chain across the two largest cogs at the front and rear.
7. Now you will need to test ride your bike to make sure that the gears aren’t slipping.
8. Run through all the gears one by one and try testing it where there will be some pressure on the chain such as climbing. If your gears are slipping then you may need to change some or all of your transmission, so don’t leave the test ride until the last minute.
Overtime bicycle parts begin to wear, this includes the bike chain. A worn chain will still lead to unequal distribution of force on the teeth on the chainring and will wear the teeth down in the same way the cassette wears.