You can remove a chain link with a chain tool in about five minutes
To take a link out of a bicycle chain, you use a chain tool (also called a chain breaker) to push the pin that holds the link together out of the chain. The pin slides out, the link separates, and you can remove it. Then you rejoin the chain by pushing the pin back in from the other side. The whole job takes five to ten minutes once you have the right tool.
You will need a chain tool — a small metal device that costs $8 to $25 and works on most standard chains. Some multi-tools include a chain tool, so check what you already have. You will also need a clean, flat work surface and good light. Wear old clothes because chain oil stains.
Key Takeaways
- A chain tool pushes the pin out of the link; the pin is what holds the chain together, not glue or welding.
- You need to know how many links to remove — usually one or two — before you start, because removing too many makes the chain too short to shift properly.
- The pin can break if you push it all the way through; stop when it is almost out and wiggle the link free by hand.
- When you rejoin the chain, the pin goes back in from the opposite side, and you push it until it clicks into the grooves on both ends.
- A chain that is too short will not allow your derailleur to move freely and can damage your bike when you shift.
Measure how many links you need to remove
Before you touch the chain tool, figure out exactly how many links to take out. Count the links on your current chain and compare it to the manufacturer's spec for your bike — this is usually in the manual or on the manufacturer's website. If you do not have that, a general rule is that a road bike chain should be long enough that the rear derailleur has about one inch of slack when the chain is on the smallest cog in front and the largest cog in back.
If you are shortening the chain because it is worn or damaged, remove only the bad section. If you are shortening it because it is too long, remove links in pairs (two at a time) so the chain stays balanced. Mark the links you plan to remove with a marker or tape so you do not lose count while you work.
Position the chain in the tool and locate the pin
Place the chain on a flat surface with the link you want to remove facing up. Slide the chain into the chain tool's slot so that the pin of the link you are removing sits directly under the tool's punch — the small metal rod that will push the pin out. The punch should line up with the center of the pin, not off to the side.
Look at the pin from the side. You will see it sticking out slightly from both sides of the link. The chain tool's punch will push it straight through. Tighten the tool's handle or screw so the punch touches the pin but does not move it yet. This is your chance to check alignment before you explore pressure.
Push the pin out slowly and stop before it falls through
Turn the chain tool's handle or screw slowly and steadily. You will feel resistance as the punch contacts the pin. Keep turning. The pin will start to slide out of the link. Watch from the side — you want to stop when the pin is almost all the way out but still has a tiny bit sticking through on the far side.
Do not push the pin all the way through. If it falls out completely, it is much harder to get back in straight, and you risk damaging the pin or the link holes. When you see the pin is almost out, stop turning and remove the chain from the tool. Wiggle the link gently by hand — it should separate from the rest of the chain. If it does not move, push the pin out just a hair more and try again.
Remove the link and prepare to rejoin the chain
Once the link is loose, slide it off the chain by hand. Wipe away any dirt or old grease from the ends of the chain where they will rejoin. Look at the two ends — one end will have the pin sticking out slightly, and the other end will have a hole where the pin goes back in.
Line up the two ends so the holes are facing each other. The pin from one end should slide into the hole of the other end. If the ends do not line up easily, the chain may be bent. Gently straighten it by hand or lay it flat and press down. Do not force the ends together — they should come together smoothly.
Push the pin back in from the opposite side
Place the rejoined chain back into the chain tool, but this time position it so the punch will push the pin in from the opposite direction. The pin should slide into the hole on the other side of the link. Turn the tool's handle slowly. You will feel the pin slide in and then suddenly stop — this is the pin seating into the grooves on both sides of the link.
Push a little further after you feel the stop. The pin should click into place with a slight resistance. Do not over-tighten — you only need enough pressure to seat the pin fully. Remove the chain from the tool and check that the link moves freely. It should bend and flex like the rest of the chain. If it feels stiff or stuck, the pin may not be fully seated; put it back in the tool and push a tiny bit more.
Test the chain and check for stiffness
Flex the chain by hand in all directions. Every link should bend smoothly. If one link feels stiffer than the others, it is a stiff link — usually caused by the pin not being perfectly centered or the link being slightly bent. A stiff link will cause the chain to skip or jump when you shift.
If you find a stiff link, put the chain back in the tool and loosen the pin very slightly — turn the handle backward just a quarter turn. Then flex the chain again. Repeat until the stiff link moves as freely as the others. Once the chain flexes smoothly, wipe off any excess grease and install it back on your bike. Shift through all the gears to make sure the chain moves smoothly and does not skip.
Frequently Asked Questions
What if the pin breaks while I am pushing it out?
A broken pin usually means you pushed too hard or too fast. If the pin snaps, you will need to replace the entire link with a new one or buy a new chain. To avoid this, push slowly and stop before the pin comes all the way out. Let the link separate by hand rather than forcing it.
Can I reuse the link I removed?
Yes, if the link is not damaged. Clean it and store it in case you need to lengthen the chain later. If the link is bent, cracked, or the holes are stripped, throw it away — reusing a bad link will cause the chain to skip or break.
How do I know if my chain is the right length?
A chain that is too short will not allow the derailleur to move freely and can snap when you shift to the largest cog. A chain that is too long will sag and skip. The correct length lets the derailleur move smoothly through all gears with about one inch of slack on the smallest cog combination.
Do I need a special chain tool for my bike?
Most standard chain tools work on any chain with a removable pin. However, some modern chains (like those on single-speed bikes or some high-end road bikes) use special pins that do not come out. Check your chain type before buying a tool — the packaging will say whether it works with your chain.
What if the chain will not rejoin after I push the pin back in?
The ends may not be aligned properly. Remove the chain from the tool, check that both holes are facing each other, and straighten any bends by hand. If the holes are damaged or stripped, that link cannot be reused — you will need to remove a different link or replace the chain.