How to put a Bike Chain back on a Derailleur?

Have you ever faced a slipped chain issue while riding a bike? Well, you need to be aware of how to fix it in case it happens. Other than fixing a flat tire, a bike rider should know how to put a dropped or slipped chain back. On a normal basis, a chain or gear ring is dropped when the teeth is worn out or narrow.

What are bike chains?

Bike chains are a group of links with plates, rollers and pins. These help in connecting the back and front gears which enables you to pedal. Each bike has 2 derailleurs, one at the front and other at the back. In the front derailleur, the chain moves horizontally. The rear one needs more attention as the chain moves vertically and horizontally. The chain also goes through the pair of wheels. In order to fix a chain, each derailleur should be handled separately. There are various reasons that result in slipping of bike chains. These include:

  • Lack of shifting techniques.
  • The rear casters or bike chain is worn out.
  • The length of the chain is too long.
  • Improper adjustments, etc.

Don’t worry! They can be fixed easily. You may get your hands dirty with grease but you can start pedaling soon. Let’s find out how to put the bike chain back with ease.

Male mechanic repairing bicycle

Steps to Put a Chain on a Derailleur Bike

Step 1: Check the drive chain well.

First, see if there are any broken or bent parts. If so, replace or repair the chains prior to putting it back. Not only the chains, inspect the gears and derailleurs as well. In case you had a crash, check thoroughly for any sort of damages.

Step 2: Hang the bike from a stand or flip it upside down.

This will allow you to put the chain back with ease. Also it prevents the bike from moving as you work. Turn the bike and let it sit on the handlebars and the seat. Place it with care to avoid scuffs and scratches.

As for bike stands, they place the bike upside down in the air. This position is apt for fixing the chain. As chains are prone to slip off on roads, you may have to get a fresh one. Place the front portion of the seat on a horizontal bar. Set the bike at a height of 1.2 m or 4 ft from the ground or high enough to keep the rear wheel off the road.

Step 3: Check on which gear the bike is resting.

The front as well as back gears have small machines called the derailleurs. These help in moving the chain from one gear to another. You need to look down at the derailleur to see where it is resting. The gear will be lined along with the derailleur. You will have to place the chain back on that gear.

Front derailleur – They are seen near the pedals. They appear like small metal covers over the cog where the chain has to be placed.

Rear derailleur – These are visible at the rear wheels. They appear in the form of mechanical arms. It slides to and fro beneath the group of gears (cassette) to help in moving the chain.

Most of the bikes will inform you about the number of gears on the handlebars. You should know how to understand and figure it out.

  • Left handlebar controls the gears at the front. It’s the smallest cog in your bike.
  • The right handlebar has control over the gears at the rear end. Those are the biggest cog in the bike.

Step 4: Move the back derailleur arm to the handlebars to loosen the chain. 

It is a tiny metallic arm at the bottom of the derailleur near the gear. A metallic square is also seen near the cog which allows you to move the derailleur. This has to bend to the front end of the bike in order to loosen the chain and hang freely.

Step 5: Use your hand to place the chain on the correct gear.

Pick the chain up using 2 or 3 fingers and place it over the correct gear. Put the other end of the chain towards the bottom end of the front cog and hold it firmly.  See to it that there is enough space to put 10 to 15 teeth into the chain groves on the cog. Gradually let go of the derailleur after placing a few teeth into the groves. You can make use of a thin stick, pencil or pen to put back the chain into the gear, if you don’t want to dirty your fingers.

Step 6: Manually pedal on the reverse for a complete rotation.

Here start pedaling using your hands. You can see the teeth you placed will guide the remaining chain to the correct groove. Complete one rotation in the backward direction. After which proceed forward for 3-4 rotations to ensure that the chain is in place and intact.

Chain tensioner:

If possible, buy this gadget known as a chain tensioner. This device can be used in multi-speed bikes which are converted to single speed. Its also used in bikes having derailleur hanger. Get it and fix it on your bike using the instructions in the manual. The package includes a head screwdriver of a particular size. This helps you to get the chain at the right fit on the bike.

Things to remember.

Here are a few things you need to be careful about while fixing the bike chain. They are:

  • Avoid placing your fingers in the chain or you may hurt your fingers, even have the fingers chipped off. Be careful while putting the chain back.
  • Tie up any loosely hanging clothing, long hair or so prior to doing the repairs on the bike chains. In case it gets tangled, it can be dangerous.
  • Wear gloves if you can, as your hands will be greasy while fixing the chains.


It is necessary to know the basics of chain repairing. As it will save you from going to the mechanic and wasting money for small faults and repairs. You also won’t have to be stranded on the streets when the bike chain slips off. This post will help you to do the job well!