Whether you’re out on the road or at home in your garage, a broken bike chain can be a real bummer. Fortunately, fixing a broken chain really isn’t that difficult, as long as you have a chain tool (also called a chain breaker). This tool fits onto the chain and allows you to drive pins into or out of the chain to “cut” it to length or take out a broken link and then reattach it by screwing the chain tool’s pin against one of the pins of the chain.
A chain tool also known as a chain breaker comes is a pretty standard accessory for multitools. Read the best multitools to find one that works for you.
Now, let’s talk about how to repair a broken chain when you’re on a ride.
When Your Chain Breaks While You’re Out Riding
If your chain breaks while you’re on the road, chances are good that you’re going to need to take the broken link out. Fit your chain tool onto your chain at the next unharmed link next to the broken one. Push the pin almost all the way through but not all the way out of the chain. Then unscrew your chain tool and remove it from the chain. To get the broken link off of the chain, flex it sideways at the point where you’ve driven the pin out.
You may have to do the same process on the other side of the broken link. When you do, make sure that the two ends of your chain (left over after you’ve removed the broken link) are complementary. One should be an internal half of a link, and the other should be an external (with pin still attached).
Fit the chain tool onto the chain in the opposite direction from how you had it fitted before (so that the tool’s pin is lined up to push the chain’s pin back in). Then screw the handle of the chain tool in to push the pin into place and reconnect the chain.
At this point, the link you just reattached may be a little bit stiff. If you have some chain lube with you, put a drop on the link. If not, that’s okay, too. Just flex the chain from side to side a couple of times and then up and down a few times. The link should loosen, and you should be able to get home without any trouble.
Once you get home, you should take a look at your entire drivetrain and see if you can diagnose what happened to cause the chain to break. If you can’t find the cause and/or if it looks like something is wrong, take your bike to your favourite local shop and get a professional bike tech to take a look at it for you. Then you’ll know if you need to make more repairs or if your bike is good to go for a few thousand more miles.