Technical Tuesday: How To Fix A Broken Chain

May 11, 2010
by Mike Levy  
For the sixth episode of Technical Tuesday we'll explain how to fix a broken chain and how to properly use a chain tool. Inside you'll find step by step instructions and a great How-To video running you through this repair.

Read on...While breaking a chain may not be quite as common as it once was, it can still quickly ruin a good day on the bike. And if you haven't yet broken a chain while miles out in the bush, your time is coming! Unlike some other mechanicals, if you don't have the proper tools and knowledge to sort out this problem on the trail, it will mean that you are dead in the water. A chain tool is a mandatory piece of equipment that should always be in your backpack. Thankfully this only requires a single tool to fix and can take just minutes once you have the technique nailed down. Below you'll find step by step instructions and a How-To video.

Watch the video to learn how to use a chain tool to fix your broken chain:

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Step By Step Instructions On How To Fix Your Broken Chain:

Tools needed: Chain tool or multi tool with built in chain tool.

Multi tool with built in chain tool

Before you start this job it is important to figure out what make of chain you have on your bike. If you have a Shimano chain on your bike you'll either have to reconnect it by using another company's reusable link, or by inserting one of Shimano's new pins. If you do not have either of those items you can still follow the steps below in order to get your bike back on the trail and yourself out of the bush, but be sure to be careful as the new connection will not be as strong as if you had used the new pin and could fail. I would recommend taking it to your local shop to have them fix it before you hit the trails again.

There are a number of reasons why your chain could have broken and there are many riders out there who swear by one brand over another. The truth is that any and all chains can break, but there is always a good reason for it. The causes could range from a bad shift under load that caused an outer plate to separate from the pin, large amounts of wear, or even incorrect installation in the first place. Despite a lot of riders insistence that it must be down to their leg strength, this is never the case as there is always an underlying cause. The chain may have broken while you were practicing your gate starts, but your meager amount of ponies wasn't the root cause of the problem!

1. The first thing to do is to remove the broken chain from your bike. This will make it much easier to remove the damaged links and check for any others that may be twisted and cause your bike to skip under load. When you look at the breaking point on the chain you may see a number of different things. Depending on how the chain snapped, you may be left with any number of combinations of male (inner links) and female (outer plates), but to put it back together without using a replaceable link you'll need to use your chain tool and make one end a male end and the other a female end.

Damaged chain link that needs to be removed

2. Now lets start by removing the damaged pieces. Some chain tools feature two different slots to put the chain in. The inner most position is strictly for fixing stiff links that may arise after you fix the chain, but you'll only ever use the outermost position to install or remove links. If your chain tool only has one position then you don't have to worry about this. One more thing to note is that some chain tools use a threaded dial to fit different width chains. If this is the case with your tool, simply turn the dial in after you've placed your chain in the slot. This will hold it in place as you work on it. As you are doing this, you'll only want to remove the damaged pieces in order to keep the chain as close to its proper length as possible. In order to produce a male end (inner link) simply push the chain pin completely through and out the opposite side. The outer plates will fall away and you'll be left with only the inner link. Take care not to let the roller (round piece that can be found between the two inner plates) fall out as they sometimes are prone to doing so.

This chain tool has both an inner position to help loosen stiff links and a standard outer
position to drive the chain pin in or out.

3. The next step is to make a female (two outer plates) end on the opposite end of the chain. This is the tricky part. Once again, put the chain in your tool's outermost position and make sure that the tool's pin is perfectly lined up with the chain pin. Begin to push the pin, but the key is to stop before it is completely through. The goal is to push it out far enough to allow you to remove the damaged bits, and if done right you'll have to flex the two pieces to snap them apart. Once apart, you should have close to a millimeter of the pin protruding towards the inside of the female outer plates. If you happen to accidentally push the pin all the way out, you'll have to restart on a new section of chain as it's not recommended to try and reinstall the wayward pin. Leaving the chain pin protruding slightly to the inside will also make it much easier to join the chain once it's on your bike, as it will snap together and you won't have to hold it.

New female end on the left, male on the right

4. Now you're ready to reinstall the chain onto your bike. In order to have the least amount of chain tension to make it easier on yourself, shift your rear derailleur to the smallest cog position and your front derailleur (if you have one) to the smallest ring position. Feed the chain through on the route that it would normally take, but be sure to have the pin that you just pushed mostly out facing to the outside of the bike so it is easier to work with.

Chain pin facing out and ready to be reinstalled

5. Join the two ends of the chain together. If you've pushed the pin on the female end just the right amount, you should be able to snap it together and not have to hold it from coming apart. If not, you'll struggle to keep it from springing apart as you use the chain tool to push the pin through. One trick is to take a 4" section of old spoke and bend it into a "C" shape, using each end to hold the chain together. Before you begin to push the pin back into the chain, take a few seconds to make sure that everything is lined up. If the chain pin is not lined up perfectly with the holes in the outer plates, it will damage them as it passes through and the chain will not be safe to ride. When you're happy that everything is lined up, begin pushing the chain pin through until there is an equal amount protruding on either side of the outer plates. Depending on your chain, the ends of the pin may be very close to flush with the outer plates. The important part is that both sides are equal. Inspect the new joint carefully for any damage to the chain such as plates that were bent out during installation.

Using the chain tool to reinstall the chain pin

6. There is a good chance that the chain does not rotate freely at the new joint. This is because the outer plates have been squeezed together in the chain tool as you pushed the pin through. You can easily spot a stiff link when pedaling backwards and watching it go through the rear derailleur's pulley wheels. There are two ways to deal with this, you can use your hands or use your chain tool to fix it. I prefer to simply use my hands. Place one hand on each side of the chain with your thumbs close to the stiff link. Using some effort, flex the chain side to side directly at the offending link. It should only take one or two tries until the new joint turns freely. The alternative method is to use the innermost position on your chain tool to give the pin at the stiff link only the slightest nudge. This is also an effective method of freeing up the stiff link.

You can use your hands to free up a stiff link

7. Before you jump on your machine and start sprinting away, always check to make sure that you've done the job correctly. There should be no bowing or cracking of the outer plates at the new joint. Run through your gears and take a few cautious pedals before going out and wheelie dropping off your balcony! Keep in mind that you've removed chain links and the chain is now shorter than it was before you broke it. If the chain was already at just the right length, it may be too short now when in the bigger cogs. Be very careful otherwise you'll end up installing a new rear derailleur and hanger!

Past Tech Tuesdays:

Technical Tuesday #1 - How to change a tube.
Technical Tuesday #2 - How to set up your SRAM rear derailleur
Technical Tuesday #3 - How to remove and install pedals
Technical Tuesday #4 - How To Bleed Your Avid Elixir Brakes
Technical Tuesday #5 - How To Check And Adjust Your Headset

Have you found this tutorial helpful? Share any of your hints or tips below!

Author Info:
mikelevy avatar

Member since Oct 18, 2005
2,032 articles

  • 20 1
 I think its good to show the basics......there are many riders out there who really know very little and they have to learn from somewhere.... why not pinkbike?
  • 17 1
 Likin' the how-to vids, thanks guys
  • 7 1
 I'm just going to ignore all the haters this time. Fixing a broken chain is a USEFUL skill, and there are A LOT of people who don't know how to do it.

What would be worth mentioning, I think, is the quick link. I always carry around at least one. I find that fixing the chain (as mentioned in this article) is actually a bit finicky, and I always end up with either a sticky link, or a weak link (and a shortened chain). The Quick Link saves time, and fixes your chain like new. And it's a very inexpensive option.
  • 3 0
 i agree, i think if they had a few more tips in tricks and not just the basic reassemble it would help.
  • 5 0
 Maybe if some of the people in my area see this I wont have to be the only person in the entire town that knows how to fix a chain.
  • 5 0
 Do Pinkbike charge you to read this article? - No. Is Pinkbike a rad website? - Yes! Stop whining you baby, two balled bitches!
  • 3 0
 Keep in mind one of the tougher things to do is please your entire audience. There are people out there that take thier bike to an LBS for new tubes, replace reflectors, etc. Pinkbike has to balance the difficult articles with the easy ones. I'm glad to see ANY How-To Video up.
  • 3 0
 The only bad thing about this sport is all the self centered haters, weight weenies, and technical tits. Some one took the time to help some one else and even though it is not you they may be helping, they are helping. For some one to take their time to do there job and to do it well should begit acclamation and heaven forbid a thank you! It is time for all you insecure idiots to face the facts riding a bicycle into adulthood is in no way or form cool! and in no way should be taken as seriously as cursing a poor man for doing a job! Face facts no matter it DH, XC, DJ, street... we are all just enfants tryiny to fight growing up! This is what we should accept and embrace cuz really isnt this why we do it.! PS. if you are having ill thoughts, or correcting my spelling and or grammer you are the person for whom i speak about!!! Last one down is a rotten EGG!
  • 2 0
 I'm a year or so late to this discussion, so forgive me, but readers should keep in mind that the link they repair will not result in a good-as-new chain link (this is especially true of many Shimano and Campy chains). So by all means take advantage of this how-to for fixing your chain in a pinch, but know that you should should really replace the re-assembled section of chain with either a quick link (e.g., SRAM Powerlink, KMC Missing Link) or designated chain pin (Shimano has specific pins for 8, 9, and 10-speed chains, as does Campagnolo for their chains). Personally, if I break a chain, it's a sign that I'm due for a new one.

Just my 2 cents. Not hating on PinkBike or anything! I'm really stoked that they are sharing this information in fact. :-)
  • 2 0
 I stumbled upon this article and accompanying video, and it "saved the day" -- I had absolutely no idea that I could use my chain tool to push a connecting pin out, but not all the way, and then re-insert it. Enough years of riding that, perhaps, I ought to have known, but I didn't... and this was the first chain I'd ever changed. PB changed a nightmare into a "been there, done that". Thanks!
  • 1 0
 fairly simple but its a bitch to do without a chain tool luckily i had a maserlink handy. i was in a forest with some ladders and the chain breaks si i find a nail a rock and start hammering away at the link until finnaly after hours of work the chain comes back broke 5 minutes from my house because i still had the broken link in
  • 2 0
 I do think there needs to be more advanced how to's. like how to replace fork seals. this is one thing people just dont know how to do or why they need to, but it's extremely important and fairly easy
  • 1 0
 Am I the only one that recognizes that you should never push an old pin back in? That's why so many people break chains . . you need a new pin every time you push one out. Every shop will give you a 9-speed or 10-speed connecter pin if you ask for it - it has extra little ridges to keep it in - much safer than using your old one!
  • 1 1
 Only Shimano chains require new pins (if not using a replaceable link) =)

Other brands can be reconnected with the original pin, or by a replaceable link.
  • 2 0
 My mistake then, I've only ever had Shimano chains (for geared bikes). Still, a huge number of people use Shimano and it wasn't mentioned.
  • 2 0
 Second paragraph, in italics =)
  • 2 0
 Yay! Good man.
  • 1 0
 At our bike shop, we're told that we can only mend 9+ speed chains with appropriate linking devices, such as powerlinks, hyperglide pins, etc; I've also had many chains snap on me when mending a chain like this then cranking really hard. Anyone else know what I'm talking about, or is this b/s? I wanna know!
  • 3 0
 Most of my friends need to watch this. I use to always fix my buddy's chains on the trail.
  • 2 0
 i would nothave been able to do this if it werent for this genious information
  • 1 0
 For some people its easy to do a truing at home i do it at home . But before i learn how to do the truing i would always give it to the bike shop.
  • 4 2
 is everyone involved with this site 16?
  • 2 1
  • 1 0
 Oh come on, its not hard to use a truing stand for christs sake, and its a tad mroe accurate than using the frame.
  • 1 0
 good work, keep em coming, lots of people need to know the stuff covered in tech tuesday!
  • 2 0
 Perfect timing, just snapped my chain an hour ago.
  • 1 0
 Great tip! Now I can take the trails home and not ask someone to give me a ride! Thanks PB!
  • 4 5
 how bout tuning gears or adjusting the brakes.....this only takes a few tools aswel so alot of people could do it at home
  • 11 1
 how about reading before you post.
  • 1 2
 good luck with that shitty chain tool...
  • 2 4
  • 3 0


Every brake needs a slightly different technique, more to come...
  • 4 0
 philipstonier just got vaporized by a knowledge bomb.
  • 1 0
 well no shit look at that
  • 5 0
 you may have threaded it. in that case steal one off someone elses bike. however this will require further instructions.
  • 4 0
 I went to that place, with the bikes yyyyyy, people told me do things I don't, take a cap, wheel must rotate nooot, a man said. uuaaaghhhyy put on the stick coming out of the wheel, turn with thy fingers down so stay the cap on ndeeee beeeee... then I log in to the forum and ask questions beeeeee becauyyyaaaaa ghhhh- se bacause I thought it was a joke funny that is yyybeeee to talk it on the man that fix chain yyy. I am so funnyyy yyy. valve cap top on yyyyyyy funny laugh people
  • 1 0
 hahah oh WAKI if i actually sit there and anuciate that whole thing properly i can almost hear you saying it from Poland.
  • 2 0
 well I actualy sit in Sweden, but where exactly do you see the relation between my comment and my location/fromcoming?
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