Even partially off, it’s a struggle to get a bike chain back in place.
Whether it fell off or you needed to replace it, this is a task many bicycle owners eventually face.
It’s not as hard as you may think, though, and my full guide should help.
Here are the basic steps on how to put a bike chain back on:
- Thread the chain through the rear derailleur.
- Fit the chain over the rear sprocket.
- Repeat this on the front derailleur and sprocket.
- Attach the chain ends together.
There’s a bit more to it than that, though, so let’s walk through it from start to finish.
How to Put a Bike Chain Back On
Before we start, I recommend giving the chain a once-over.
- Loose rivets in the links.
- A lengthening chain—12 links should measure 12 inches.
The latter is particularly important. Why else would your chain have slipped or fallen off? Be sure to repair your chain if it’s broken or too long. I’ll give you some advice on this later.
Once all is well, move on to reattaching it.
Step 1: Prep the Bike
You could secure your cycle then get to work. But, I find it most accessible to flip the bicycle upside down.
Before you do this, adjust the gears until the derailleurs are in place:
- By the small back sprocket.
- Near the smallest front chainring.
Once flipped, ensure the handlebars are straight for best balance.
Note: A sprocket is the cog-like wheel. The derailleur is a 7-shaped part, with two round bits at the top and a cog-like part at the bottom.
If you’re unfamiliar with this area of your bicycle, perhaps it’s best to familiarize yourself with it before beginning. Examine the area, look up a diagram, then come back to the task.
Step 2: Thread the Chain, Part One
- Locate the rear derailleur and sprocket—they’re the farthest to the left on the back wheel.
- If there’s a cable connected to the rear derailleur, ensure your bicycle is in the highest gear.
- Thread the chain through the derailleur and onto the sprocket.
- To do this, slot the gear’s points through the chain links. Turn the sprocket as you thread the chain onto further links.
You’ll need to split the chain to do this:
How to Split a Bicycle Chain
Most bicycle chains have a master link. It’s relatively easy to split the chain here using chain pliers or regular, thin pliers.
With no master link, you can use one of two methods to split the chain:
- With a chain tool: Clamp the chain firmly in the tool. Keep twisting until the rivet pops and the chain splits.
- Without a chain tool: Gently tap a small nail against the rivet. Use the pliers to hit the nail, as a hammer would be too heavy. Do this until the rivet pops out and the chain splits.
Step 3: Thread the Chain, Part Two
Now it’s time to tackle the front sprocket. This is the larger of the two cog-like creatures on your bicycle. It will have a smaller cog-like part on the back of it.
This is where you thread the chain. It doesn’t go onto the larger sprocket, but the smaller one attached to its back. And, if there’s a front derailleur, you must also thread it through that:
- If there’s a cable connected to this derailleur, ensure your bicycle is in the lowest gear.
- Thread the chain through the front derailleur, if present, before tackling the sprocket.
- Place the chain as you did with the last sprocket, going slowly and gently. You don’t need to thread the entire chain on; that comes later.
Note: You can switch steps two and three if you wish, putting the chain on the front derailleur first.
Step 4: Pedal
Slowly push on the pedals to get the parts moving. The chain should move with them, hooking on as much as it can.
Pedaling here will let you see if there are any placement issues. With no issues, the chain should fall seamlessly into place—all that’s left is to reattach the chain to itself.
Note: If you have a slipped chain, slow and gentle pedaling may put it back in place. No need to remove and reattach it!
However, this doesn’t always work, so you may need to get more manual…
Step 5: Reattach the Chain
If you don’t know how to reattach the chain, it’s simple:
- Line up the loose ends of the chain to each other.
- Use a screwdriver to firmly push the rivet into place.
- When the rivet clicks, you’re done.
If your chain split accidentally, and you lost the rivet, don’t worry. Any reputable bicycle dealer should be able to provide one.
Now your chain should be back in place and functioning well.
Tips and Tricks
There are a few things to keep in mind while placing the chain.
- A tab in your derailleur: If you see a tab-like area in your derailleur, make sure the chain doesn’t touch it.
- There may be no back derailleur: If you have a single-gear bicycle, you may be missing a derailleur. This is fine—just thread the chain over the cog instead.
- Utilize a C-hook: A C-hook holds the split chain’s ends close together. This helps you thread it without it being too tight but without worrying about loose ends.
Why Did My Chain Come Off or Slip?
The main reason a chain slips or falls off your bicycle is that it’s too long. It may not have been too long to start with, but over time, it stretched out.
But wait—don’t run to replace it just yet. You can shorten it! Usually, two or three links will do the trick, and it’ll be like new.
There are two ways to shorten your bicycle chain, with or without a bike chain tool. It’s easy, especially with the tool:
- Clamp the chain in the bicycle tool.
- Slowly and gently twist the tool’s handle.
- The rivet in the link you wish to remove should pop right out.
- Reattach the chain and see if it sags or slips.
If you find yourself in trouble, where the chain is always too long or too short, it’s time to replace the chain. Look up your bicycle model, and see if the manufacturer provides replacement chains.
Forgoing that, you can get one online.
How to Prevent Your Chain Slipping
Keeping your chain clean and well-lubricated can help prevent it from slipping. I recommend cleaning it weekly and re-lubing it once it dries. You can speed up the drying process with a compressed air canister.
That said, there’s no way to outright prevent your chain from wearing down. But, you can detect the issue and prevent the slipping element.
My advice is to treat your bicycle like you’d treat yourself. You need a doctors’ checkup every year or two. Your bicycle needs one every few weeks or months, depending on the frequency of use.
Luckily, you can learn to perform the checks yourself by ensuring:
- The chain isn’t stretching: Measure a few chain links often. If the measurements change, it’s stretching.
- Check for visible signs of wear: If you notice any chips or weathered areas on the chain, it’s time to replace it before it slips.
- Inspect the chainrings: If your chainrings have chips or worn areas, you need to make changes, too. The chain isn’t the only one at fault!
- Check everything is aligned: If your bicycle has recently taken a hit, some components may be out of place. Check up on them or get a tune-up. A bike mechanic will spot this issue easily.
General Chain-Care Tips
Apart from ensuring it doesn’t wear down, there are ways to care for your chain to add longevity.
Check for Rust
Chains can rust easily, especially if you go a few weeks without cycling. It’s hard to miss a fully red and crunchy chain, but a little rust can go over your head.
I recommend flipping your bicycle upside down every month and checking the entire chain for rust. You can easily remove a small amount of rust, often without removing the chain.
However, larger amounts take an in-depth knowledge of how to remove rust from a bike chain.
Keep It Clean
Your chain can easily pick up dirt and grit. I recommend wiping it down every week with a dry rag. You can use a wet rag if you’re willing to dry it and commit to anti-rust spray too.
Then, every few weeks or months, depending on use, do a deeper clean. You can use a bicycle chain cleaning kit for this. Luckily, you can leave the chain on to clean it.
I lubricate my bicycle chain every week, and I’ve rarely had issues. You can do it less if you cycle less, but keep it regular!
Your bicycle chain slipping isn’t the end of the world, unless you’re a novice and struggle to fix the issue.
Remember to measure your chain regularly. A slipped chain can damage your cycle if you ignore it. And, a damaged bicycle can equal a damaged you.