How to replace a bike chain

December 03, 2019 4 min read

How to replace a bike chain

Some parts of your bike are weaker than others and require your frequent attention to maintain. One of these consumable parts is your chain. Getting to know how to repair, change or alter your bike chain is one of the most useful skills you can learn so you can maintain your bike or get yourself out of a tight spot (like a broken chain when you are on a beautifully quiet road) quickly and easily. 

The great news is you can use this skill on any bike, there is no difference across touring bikes, road bikes or mountain bikes. 

In most cases drive chain components are compatible across all brands and manufacturers, with the standard chain size for derailleur chains being 3/32-inch, however subtle differences in materials, width, height and manufacture can cause issues with shifting performance like slipping, sticking, looseness or elasticity and faster wear and tear. 

You also need to take into account the correct chain width for your cog configuration front and rear. 

As a guide here are the numbers for standard derailleur bike chains 

 

Rear cogs

12 sprockets = 5.3 mm

11 sprockets = 5.5 mm

10 sprockets = 6 mm

9 sprockets = 6.5 to 7 mm

6, 7, and 8 sprockets = 7 mm

 

Front chain ring speed

8-9 speed is a wider chain

10-11 speed chain is more narrow 

 

The very best way to know if your chain fits well is to have on hand an identical chain made from the exact same materials as your current one. Typically, your new bike will come with identical branded components, however, if your chain, derailleurs, cassette and shifters are all different brands it’s best to ask a professional mechanic for advice on which chain to have available for back-up. 

A note about quick links

Some chains come with a quick link (or masterlink) with purchase, which allows them to be opened quickly. These can be reusable but not across every brand. If your chain currently doesn’t have a quick link you can install one using the instructions here for …  provided your manufacturer has links available for your chain. 

Quicklinks are handy for changing and even cleaning your chain with minimal fuss. 

How to replace a bike chain

Tools for the job

  • Chain checker
  • Chain breaker (also called a chain splitter)
  • Thin rod (or save a piece of broken spoke)
  • Quality quick link pliers 

Remove the old chain 

If you have a quick link you may need to use a screwdriver to flick it open. If you don’t have a quicklink then use a chain splitter tool to push out one of the chain pins from the lower stretch of chain. Once the pin is out, remove the chain from the bike carefully. 

If your chain needs work because it broke while you were riding, you can skip this step. 

Have you been running a worn chain for a while? You may have damaged your cassette by wearing down the teeth. It’s best to change booth components at the same time and start fresh.  Changing your chain regularly will prevent the additional cost of needing a new cassette. 

Set a new chain

If the chain is worn you will need to install a new one. You simply need to …read the instructions below 

To get your bike ready shift to the biggest cog on the rear derailleur and the biggest chainring on the front (this gives you the shortest distance front to back). If you have a rear derailleur with a clutch mechanism release this as well. 

Next, run the end of the new chain through the mech, around the outer chainring and thread it through the front derailleur. Turn the cranks slowly to pull it through and give you a few inches of free chain.

Take the other end of chain and place it inside the seat stay. Lay it over the cassette and pull down on the rear derailleur. That will leave the derailleur open so you can thread the chain up, over the top of the upper jockey wheel and behind the derailleur cage arm tab. After that continue over the lower jockey wheel and finish through the lower tab. Now it’s time to release the derailleur gently. 

Make sure your size is correct

When to seal the ends together depends on the size you need to run smoothly in any gear.

We’ve already started in the biggest chain set possible so leave everything as is in order to set your chain size.

Make sure your chain is threaded through correctly then pull the ends together firmly and see where the rivets need to join up. You can hold them in place or you can use a broken spoke or wire to secure the two pins and free up your hands while you measure the best one to split. How your chain connects will depend on brand and that can change the finished length so it pays to have hands free while you juggle the required pieces. e.g. Shimano will use one inner and one outer plate at one end only, SRAM will use two inner plates at both ends. 

Look to have the chain firm but with some movement maintained in the derailleur arm. 

When you are sure you have the right length split open the piece that you want to connect using the chain breaker tool. 

Manually move the chain to the smallest cogs to check the fit and get ready for the next step. 

Seal the deal

Now it’s time to close your chain off. The technique you use will be different depending on the chain brand. If you’re using Shimano take the two ends and insert a joining pin using the chain tool. Once the pin is in place snap the end off with pliers.

If you’re using KMC or SRAM it’s as easy as inserting the connector links by hand between the two ends. The plates will snap together to join. If you don’t have pliers to bring the plates together you can pedal the connector link to the top of the chainstay, hold the rear wheel tightly and put pressure on the closest pedal until the link is fully seated. 

Final check

Now that your chain is connected, run your bike through the full gear range to check it is working smoothly. 

Having a clean and well maintained chain that works with you on a ride? That’s freedom!


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