How To Fix a Dropped Chain


Photo by Tristan Von Duntz

Photo by Tristan Von Duntz

This is the second in a series covering common bike repairs in a mountain bike trail setting, including repairing your flat tire Many of these repairs can be applied or adapted to road bikes as well.


What’s the most important part of a bike? Arguably, the chain. Wheels are a critical component, but they wouldn’t roll if it weren’t for the chain—or at least they wouldn’t go uphill. What does it take to keep this critical but often-overlooked part of your bike functioning? Read on to learn how to fix a dropped chain.

Damaged drivetrains and misaligned derailleurs are common problems leading to a dropped chain. When your chain drops, and if it is a persistent problem, be sure to check the chain rings and cassette cogs for damage like bent or broken teeth.

As always, work off the trail so as not to impede other riders.

In Your Pack

No tools required!

The Repair

A dropped chain, though annoying, is easy to fix. Get off the bike and steady it in an upright position against a tree, rock or sign post. Push the rear derailleur toward the pedal (forward or inward) to add slack to the chain, and then use your other hand to free the chain from the chain rings, cassette or pedals. Line the chain back up with a chain ring and cassette to put the chain back in place.

Lift the rear of your bike a few inches of the ground and give the pedals a few turns to allow the chain to find its gear. This last step is important, because simply hopping back on your bike and pedaling away will put stress on your chain while it clunks back into place, causing further wear and damage.

On the Fly

With practice, you can even correct a dropped chain without getting off the bike. If you can do so safely, look down at the chain rings to watch the chain as you coast along. Pedal backward a quarter- to half-turn and then pedal forward again, slowly. Watch for your chain to catch on the teeth of your chain rings. You may need to repeat this ratcheting once or twice. Shifting your front derailleur may help, too.

Ride On

With your chain back in place, you’re good to go! Once home, be sure to keep your chain clean and lubed, as gunk in the chain can lead to shifting problems and dropped chains. If a dropped chain is a persistent problem, it’s a good idea to drop into your local bike shop after your ride to check for issues with your drivetrain that may have caused the dropped chain. Quick adjustments to derailleurs or a general tune-up can solve most drivetrain problems. Happy trails!

Last modified: July 22, 2014

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