If you’ve ever had your bike chain pop off mid-ride, you’ll know it can be a real nuisance. If you know how to put it back on, you can be off on your way again in a few minutes. But if you don’t know what you’re doing, it can be a very frustrating experience.

Slipped, damaged, or worn-out chains are common, and knowing how to put a bike chain back on is one of the essential skills every cyclist needs to have. And it will save you having to fork out on expensive repairs. Fortunately, putting a chain back on a bike is quick and simple to do, and involves only a few steps to get you back on your way.

How to put a chain back on a bike

The 'drivetrain' of the bike consists of all the bits that allow you to pedal and move your bike. The key components are the pedals, cranks, chainrings, chain, cassette (cogs) and derailleur. And if you have a problem with your chain, the whole drivetrain system will come to a halt.

Shop our range of drivetrains and gear parts at Decathlon. We have everything you need to take your drivetrain system up a gear.link

If you have a problem with your bike’s chain, just follow these simple steps to get yourself going again in no time:

Step 1: The usual cause of a bike chain falling off is it coming off the sprocket. Though in this case, the chain will still be routed to the front and back derailleurs, and does not totally break. You’ll just need to find where the chain has slipped off, or where the chain is jammed, and slip it back onto the sprocket. Then, you need to rotate the wheel to complete a full cycle to ensure that the chain is back on the teeth again.

Step 2: If the first step didn’t work, you could have a seriously jammed chain. This usually means the chain is jammed between the rear sprocket and the frame. You’ll need to identify the quick release of the rear wheel and loosen it. Next, you’ll need to pull the lever located at the centre of the rear wheel, and open the quick release. You’ll need to loosen the nut, too. You should now be able to loosen the chain. Check whether the chain is broken or worn out before putting it back on, ensuring there are no loose plates or components so it doesn't get jammed again.

Step 3: After thoroughly inspecting the chain, you can put it back to its original position. This time, you need to thread the chain back in by using your bike pedal. Hop on your bike and pedal forwards gently and steadily until you feel that the bike is now using the right gear. You will notice that the chain will go right back into the gear where the slippage happened. If this doesn’t happen, you can keep changing gear until the chain slips back into its original position, and the pedals are running smoothly.

Step 4: Now you have your chain back in its place, you need to perform some final checks. This time, make sure you’re using a comfortable gear. You can change your bike gears on both the front and back derailleurs and see whether the gears produce any noise. If you didn’t hear anything strange, then the chain is back to its original position.

Note: For the less jargon-savvy cyclists, a sprocket, refers to an individual gear within the cassette/block. The front gears are referred to as chainrings, or as a crankset. And the derailleur’s job is simply to ‘derail’ the chain. In doing so the chain moves from one cog to another – that’s how your gears work. Most modern bikes have front and rear derailleurs to manage shifting between the chainrings (front) and the cassette (rear).

How do I stop a bike chain from coming off?

In order to stop a bike chain from coming off, it’s important to understand why it does fall off. The chain is usually made from hardened steel, with steel plates stitched together by rivets. And it’s vital for transferring energy from the pedals to the wheels. The steel plates are highly durable and flexible, and they bend as you travel using a drive mechanism coming from your bike derailleur.

Here are the major reasons why your chain might slip off so you can help prevent it from happening:

  • Loose part: This is one of the most common reasons why your bike chain may be slipping off. Therefore, it’s important to thoroughly check your chain regularly to identify any loose parts. The chain has four main parts: the inner plate, outer plate, rollers and pin, and when you hear a rattle, or notice a part moving when you wiggle the bike chain, you can simply tighten it up.
  • Worn-out chain: Your chain will not perform well on the road if it’s damaged, bent, or worn. Make sure you replace your chain around every 2,000 miles to keep everything running smoothly.
  • Long chain: If you’ve replaced your bike chain with one that’s too long, it will fall off. The chain needs to fit your bike perfectly, so it's important to measure your bike and the chain you will use to ensure a good fit. You can always remove some of the links in the chain until it fits correctly.
  • Shifting too hard: Most bikes come with seven gears used for shifting. If you accidentally shift your bike too hard, your bike chain can come loose as your bike derailleur over-extends itself.

How often should I clean my bike chain?

Looking after your bike doesn’t have to be difficult, and if you take care of it, it’ll reward you with many more years in the saddle.

Cleaning your chain regularly will help keep your bike in tip-top condition. And first thing’s first, you need to get the grease, mud and dirt that’s bound to build up on your bike’s drivetrain off. If you don’t degrease your bike before cleaning, you’ll just be moving muck around. You should aim to degrease your bike at least once a month. And then give it a good clean to make everything shine.

How often should I lubricate my bike chain?

Once you’ve cleaned your bike, it’s important to lubricate it. Lubricating your bike is the fastest, cheapest way to maintain your bike and it only takes 15 minutes! Lubricant or “lube”, increases the lifespan of your drivetrain by reducing friction. And this isn’t an aesthetic thing, it really does need to be done to make sure your bike moves in the way it should. So we recommend you do it every two weeks or so to keep things running smoothly.

Here’s our guide to lubricating your bike.


How often should I replace my bike chain?

Other than your tyres, your bike’s chain is one of the components that needs replacing most often. And if you leave it too long, your chain will wear out. This will affect your gear shifting, and may even shorten the lifespan of the rest of your drivetrain components.

A general rule of thumb is to replace your bike’s chain every 2,000 miles to help prevent extra wear of your cassette and chainrings. Though no two chains will wear at exactly the same rate because no two riders treat their chains the same. You can check your chain with a B'Twin Chain Wear Indicator, which lets you know in seconds if it’s time for a new chain or not. If your chain does need replacing, check out our guide to choosing the right bike chain.

You can do a lot of your own bike maintenance quickly and cheaply if you know how, and have the right tools to hand. A slipped chain is common, so don’t get caught out! Remember to follow our simple steps to put your chain back on your bike, and get yourself back on the road quickly.

At DECATHLON, we have everything you need to keep your bike in tip-top condition. Whether you're rushed for time on the road (or mountain!) or tinkering in the garage, maintenance kits with all the tools, oils, sprays and spare parts are essential.