There are certain repairs that the home mechanic should be prepared to make to keep the bike’s drivetrain running smoothly and for as long as possible. Learning how to replace a bike chain can save years of wear and tear off the rest of the bike’s drivetrain like the cassette and front chain rings. Once the chain becomes too worn, it will start to wear down the teeth of the cassette and chainrings, so that if you don’t change it soon enough, you will likely end up having to replace everything, which will become a costly endeavor.
Normally, you can count on a chain being good for around 1000 miles before it needs replacing. How do you know when it’s time to replace your chain? If you feel your shifting is a bit sluggish, or the chain is even hesitating before changing gears after you’ve shifted, then it’s a pretty good chance that your chain has worn to the point that it is no longer fitting neatly and directly onto the cog teeth in the rear.
When you suspect your chain has become too worn, you can use a chain checker to measure whether the chain has begun to stretch out, which contributes to the poor performance and unwanted wear your drivetrain will suffer.
Special tools to do a proper job
It should come as no surprise to the home mechanic that there are certain tools you will need to invest in to be able to do a proper job of measuring and changing your bike’s chain. There are several high quality brands that make these tools, but no matter which brand you buy, you’ll need:
- Chain checker
- Chain breaker
- Master link pliers (normal needle nose pliers will work as well)
- Replacement Pin or Master Link (should come with a new chain)
- New chain
- Protective gloves (if you don’t want greasy hands)
Not all chains are the same. The ever-increasing number of gears, from 9-speed, to 10 to 11, 12, and now even 13-speeds means that chains are highly specific to whatever drivetrain you are using. Shimano and SRAM used to be fairly compatible – you could use a SRAM chain on a Shimano drivetrain – but with the move to 12-speed for each manufacturer, mixing and matching chains with drivetrains is no longer advisable. You. Will be more likely to have shifting issues which will again accelerate wear one the parts. Campagnolo has never been cross compatible with any other brand.
And even within brands, there is no cross-compatibility between different numbers of gears, for instance a 12-speed Campagnolo chain is not compatible with an 11-speed Campagnolo chain. When buying replacement bike chains, you need to be precise in choosing the right chain for your groupset and however many speeds it uses. Similarly, when choosing the tools you’ll need to change your chains, you should be certain that it will work with the mechanisms used by the chain. An SRAM eTap AXS road chain uses a Flattop design that won’t work with all chain breaker tools. You’ll need to be sure to find a chain breaker that can accommodate the design.
Alternatively, Campagnolo groupsets use C-Link quick-links which require a chain breaker with a peening function. That’s because you will need to cut the replacement pin when reconnecting the new chain, and peen, or hammer the pin end to increase the surface to enhance the strength of the joint.
Removing the old chain
To remove the old chain, first locate the master link or joining pin that connects the two ends. If it has a master link, use a pair of master link pliers to compress and disconnect it. If it has a joining pin, use a chain tool to push the pin out and separate the chain.
Once the old chain is removed, measure the length of the new chain to match the old one. Simply laying the new chain next to the old one won’t be sufficient since the old chain will have stretched out of shape. Not only that, but there is no guarantee that the old chain was properly sized in the first place.
Instead, we recommend that you shift the bike into the smallest cog in the rear and the smallest chainring in the front before threading the new chain through the front derailleur, over the rear cassette, using the smallest cog, and then through the jockey wheels of the rear derailleur.
Install and size the new chain
Since most chains come longer than required, you will need to be careful to size it correctly on the bike before cutting it to length. When you have threaded it through both derailleurs, the two ends will meet below the chainstay. Pull it together to the point where you have some tension on the rear derailleur without being so short it will risk damaging the components. And be certain you are joining an internal link to an external one. When measuring, if the chain uses a master link, install half of the master link. This will account for the extra half inch the master link provides. Once you are happy with the chain length, use the chain tool to remove any excess links to get the correct length.
Once you are sure you have the chain at the right length, connect the two ends using either a master link or by driving in a new joining pin with the chain tool. For bikes using a replacement pin, face the bike from the drive side, push the pin into the chain to hold it together. Push the pin home by screwing the handle of the chain tool slowly – you don’t want to rush this step since you want the pin to be precisely flush with the outside link.
Use the chain tool to snap off the excess portion of the pin, once you are certain that you have the chain at the proper length, and all links move smoothly.
Shift through the gears to ensure the chain is running smoothly.
Conclusion – extend the life of your drivetrain
Replacing your chain for the first time can be a fiddly and confusing affair. You have to be certain to buy the correct replacement chain, and then know that you have the tools that will be compatible with the type of chain you are using.
But once you have the new chain properly installed – and took the opportunity to clean the rest of your drivetrain like the cassette and derailleur pulleys – you will enjoy riding your bike as if it’s the very first time. That’s because a clean drivetrain is a happy one that will always ride like new.
You may also like our article on what is the best crank length for cycling.
