A bicycle chain replacement takes 15 to 30 minutes with basic tools
Replacing a bicycle chain is a straightforward job you can do at home with a chain tool, a new chain, and about half an hour. You do not need special training or expensive equipment—just the right size chain for your bike, a way to remove the old one, and a method to connect the new one. Most people find the hardest part is getting the chain length right, but that follows a straightforward rule.
The process breaks into three steps: remove the old chain, measure and cut the new one to length, and install it. If your chain has a master link (a removable connecting pin), removal and installation are faster. If it does not, you will use a chain tool to push out the old pin and install a new one.
Key Takeaways
- A chain tool is the only specialized tool you need; a 15-speed chain tool works on most bikes, but check your drivetrain speed first.
- New chains come longer than you need—you must measure the old chain or use the big ring and big cog method to get the right length.
- Master link chains (with a removable connecting pin) are faster to install than chains that require a chain tool to set the pin.
- After installation, shift through all gears and check that the chain does not rub the derailleur or skip under load.
Gather the right chain and tools before you start
Buy a replacement chain that matches your bike's drivetrain speed. A single-speed chain is different from a 7-speed, 8-speed, 9-speed, 10-speed, 11-speed, or 12-speed chain. Check your bike's shifters or count the cogs on the rear wheel to find out. The chain package will list the speed it fits.
You will need a chain tool to remove the old chain and install the new one (unless your new chain has a master link). A basic chain tool costs $15 to $30 and works on most chains. Some tools have a pin extractor on one end and a pin installer on the other. If your chain has a master link—a special connecting link with a removable pin—you can skip the chain tool and use your hands or a small screwdriver to pop it open.
Have a rag or old towel nearby. Chains are greasy, and you will want to wipe your hands and the work area. A bike stand or a way to hold the bike steady makes the job easier, though you can do it with the bike on the ground if you prop it carefully.
Remove the old chain using a chain tool or master link
If your chain has a master link, look for a link that looks slightly different from the others—it usually has a clip or pin that sticks out a little. Use a small flathead screwdriver or a master link plier to pry the clip off, then slide the chain apart by hand. This takes 30 seconds and is the easiest removal method.
If your chain does not have a master link, use the chain tool. Position the tool over any pin in the chain (not a master link, if your chain has one). Align the tool's pin extractor with the chain pin and turn the handle clockwise. Push the pin most of the way out—do not push it all the way through, or you will lose it. Stop when the pin is almost out, then wiggle the chain to separate it. You can now remove the old chain from the bike.
Wipe the chainring (front sprocket) and cogs with a rag to remove old grease and dirt. This is a good time to clean the derailleur and check that it moves freely.
Measure the new chain to the correct length
New chains come too long. You must cut it to match your bike's frame and drivetrain. The most reliable method is to use the old chain as a template: lay the new chain next to the old one and count the links. Cut the new chain to the same number of links.
If you do not have the old chain, use the big ring and big cog method. Wrap the new chain around the largest chainring (front) and the largest cog (rear) without threading it through the derailleur. The chain should wrap around both with just enough slack that you can pull it up about half an inch. Mark that point, add two more links for the connection, and cut there. This method is less precise but works in a pinch.
To cut the chain, position it in the chain tool with the pin you want to remove aligned with the tool's pin extractor. Turn the handle clockwise to push the pin out completely. The chain will separate at that link. Count your links carefully before you cut—you cannot add links back.
Install the new chain and set the connection
Thread the new chain through the derailleur the same way the old one ran. Start at the front derailleur (the small cage near the chainring), then down and around the rear derailleur (the larger cage near the cogs), and back up to the chainring. The chain should sit on top of the chainring teeth and wrap under the rear cog.
Bring the two ends of the chain together. If your new chain came with a master link, snap it onto one end of the chain, then slide the other end through it and snap the clip closed. You should hear or feel a click. If your chain does not have a master link, use the chain tool to install a new pin. Insert the pin into the hole where the two chain ends meet, then use the chain tool's pin installer to push it through. Push until the pin is flush with the chain—it should stick out equally on both sides.
Shift the bike through all the gears a few times. The chain should move smoothly between cogs without rubbing the derailleur or making noise. If it rubs or skips, the derailleur may need adjustment, which is a separate job.
Lubricate the chain and check your work
Once the chain is installed and running smoothly, explore chain lubricant to the inside of the chain while you pedal backward slowly. Let the lubricant soak in for a few minutes, then wipe off any excess with a rag. A clean, lubricated chain lasts longer and shifts more smoothly.
Spin the pedals and listen. A new chain should be quieter than an old, dry one. Check that the chain does not rub the frame or derailleur at any point in the pedal stroke. If it does, stop and recheck that the chain is threaded correctly through the derailleur.
When to call a bike shop instead
If your derailleur is bent or does not move freely, the chain will not run smoothly no matter how well you install it. A bike shop can straighten a derailleur or replace it if it is damaged. If your chainring or cogs are worn down (the teeth look hooked or sharp instead of even), a new chain will skip on old cogs, and you may need to replace them too.
If you are not comfortable using a chain tool or you are unsure about your bike's drivetrain speed, a bike shop can do the replacement for $20 to $50 in labor. It is worth the cost if you are uncertain, because an incorrectly sized or installed chain can damage your derailleur or cause the chain to drop off while you are riding.
Frequently Asked Questions
How do I know what size chain to buy?
Check your bike's shifters or count the cogs on the rear wheel to find the speed (7-speed, 10-speed, 12-speed, etc.). The chain package will list which speeds it fits. If you are unsure, bring your bike to a shop and ask, or take a photo of the cogs to a bike store.
Can I reuse the old chain pin?
No. Once you push a pin out with a chain tool, it is damaged and will not hold the chain together. New chains usually come with a spare pin, or you can buy a replacement pin for a few dollars. Always use a new pin when you install a chain.
What if the chain is too long after I cut it?
You cannot add links back. If you cut too much, you will need to buy another chain. This is why measuring twice before cutting is important. If you are unsure, cut one link at a time and test the fit before cutting more.
How often should I replace my chain?
A chain typically lasts 2,000 to 3,000 miles of riding, depending on how often you clean and lubricate it. If the chain skips under load or makes noise even after lubrication, it is time to replace it. A worn chain will damage your cogs and chainring if you do not replace it.
Do I need to replace the chainring and cogs at the same time?
Not always. If your cogs and chainring are not worn, a new chain will work fine on them. If the teeth look hooked or the chain skips on new cogs, the old cogs are worn and need replacement. A bike shop can check this for you if you are unsure.