I have a Lappierre Zesty 314 (2012). I'm running XT rear mech, an SLX front mech, my crank is XT, rear cassette is XT and XT chain. I went to the Forest of Dean and after the day was over I snapped my chain! I picked up a SRAM chain for my bike and now when I pedal hard it slips with a big bang. I have new Eastern Havens so my hub is fine. Can you help with any ideas to help me solve this? Shall I get a new rear cassette?

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    My guess is that the new chain is the wrong size, or you did not properly adjust its length when installing. Commented May 28, 2014 at 19:12
  • 1
    Also, if your chain "snapped" that suggests that something in the drive train may be bent or damaged. Commented May 28, 2014 at 19:17
  • (According to what little I find on the bike the chain is a "10 speed".) Commented May 28, 2014 at 19:18
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    Check things out before you go spending money. As well as other suggestions, is your rear derailleur ok? What happens when you put it on a stand? Does it only jump under load? Any idea what the bang is? Or where its coming from?
    – PeteH
    Commented May 28, 2014 at 19:45
  • +1 check something in your drive chain. I got a notch in my front derailleur which chews and snaps chain - so check front and back drive-train. OFTEN rear derailleur can get a bit twisted or bent. Check does your rear derailleur cog line up correctly with your rear cogs? Applying some gentle brute force to rear derailleur can help. This is very good: sheldonbrown.com/derailer-adjustment.html
    – gaoithe
    Commented May 14, 2015 at 16:40

7 Answers 7


Look up the proper chain for the components. XT is not a size - that is the group level. You should size the chain for the number of speeds (gears).

Inspect the cassette. As they wear the teeth get sharper spaces get longer. Visually compare it to a new cassette even if you are looking at a picture.

If your chain snapped then possible something else is damaged. Inspect all the drive components.

A cassette typically last 2-3 chains. If you get a new cassette then change the chain.

A worn chain wears a cassette down faster.
And a worn cassette wears a chain down faster.

A chain is cheaper and easier to change so cheaper to stay with a fresh chain.
There are tools to measure chain stretch.
Replace a stretched chain.

A new chain on a worn cassette will jump - basically both the chain and cassette stretch.

  • 1
    +1 for pointing out that a cassette should last longer than a chain. Despite other answers there's not normally a 1:1 relationship between the two.
    – PeteH
    Commented May 28, 2014 at 19:42
  • Do you suggest to change cassette and chain together? Commented Oct 21, 2015 at 6:21

Had the same problem. Just rechecked and had a stiff link where I attached the new chain. Hope that helps...

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    Welcome to SE - someone has tagged this answer as low-quality because its length. You could use the Edit link to expand your answer. Suggest you include something about how you made the stiff link more flexible, and possibly info on how it felt to ride with the stiff link. What made you check for a stiff link - was it sitting at a funny angle ?
    – Criggie
    Commented Dec 31, 2017 at 5:32

I replaced an old, barely skipping chain with a brand new one, and it skipped a lot more, right away. I finally figured out that it was too long (by 3 links), but by this point, my two most commonly used sprockets had been worn down by all the slipping.

When I was looking around for this same answer a while back, I found most people talking about worn teeth/sprockets, narrow chains, and minor adjustments. I think a properly sized chain is the best foundation for avoiding this problem, and should precede all the other troubleshooting steps. (Yet again, Daniel R. Hicks has an accurate comment - it should be an answer, so I'm making it one!)

Any chain sizing method can be used, but I used the following, and it worked well. (From https://www.ilovebicycling.com/determine-bike-chain-length/)

Largest cog and largest chainring method

The easiest way to determine bike chain length is the largest cog to largest chainring method.

Once the old chain has been removed, shift the front derailleur to the largest chainring, and the rear to the smallest. Wrap the new chain around the the largest chainring (at the rear), making sure that if the chain has an outer plate, it is routed toward the front chainring. Pass the chain through the front derailleur cage and onto the largest front chainring. Hold chain at the 5 o’clock position. If you are using a masterlink chain, install half the masterlink onto the front end of the chain to account for the extra half link the master link provides. Pull the lower section of the chain snug towards the front chainring, bypassing the derailleur altogether. Find the closest rivet where the two ends could be joined and add 2. This is your cutting point.

enter image description here

  • 1
    Good first answer, but it does depend a lot on the link remaining working. Its often best to summarise info from the remote link into your answer, so if/when it expires there's still some useful info.
    – Criggie
    Commented May 1, 2018 at 0:36
  • Thanks, when I get a chance, I'll edit to add that.
    – lead
    Commented May 2, 2018 at 15:12
  • yeah that link doesn't go
    – TT--
    Commented Apr 19, 2020 at 3:28
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    Thanks for the comment, @TT, it reminded me to update my answer.
    – lead
    Commented Apr 20, 2020 at 17:29

Chain slip, after replacing a chain, usually indicates worn cog(s) and/or chain-wheel. This can be avoided by replacing the chain early, before major wear has taken place. The snapped chain is problematic. The break could have been caused by an extremely worn chain. If the original chain had no master-link, it could be that the pin was not installed exactly as it should have been. This pin could have popped out on a well worn chain. If you still have the broken chain, re-install the chain, replacing the broken link with a quick-link (master-link). Now, does the old chain slip? (be careful during testing) If the old chain does not slip & the new chain slips, then you will need to replace the cassette in order to use the new chain. (one or more chain-wheels may need to be replaced also)


[edit: with a few more years of experience . . ] It is likely if you have new chain and an old rear cassette which is worn then that is the problem. A new cassette will match teeth on new chain.

But the problem could also be with your new chain length or rear derailleur. Happily not expensive just can be a bit tricky to fix.

Three things to check:

  1. New chain is the right length? The new chain should have the same number of links as the old chain. Did you line up old and new chain (allowing for wear so the line-up will be asymmetrical!) and put on new chain with the same number of links? I used this recently: http://www.bicyclinglife.com/HowTo/ChangeAChain.htm The old chain will be "stretched" so will not line up exactly with new chain.

  2. OFTEN rear derailleur can get a bit twisted or bent. You were riding in the forest and chain snapped. Might you have bumped something? :-) Especially your rear derailleur is exposed to bashing off things when mountain-biking. Check does your rear derailleur cog line up correctly with your rear cogs? Applying some gentle brute force in the right place on the rear derailleur can help. This is very good: http://www.sheldonbrown.com/derailer-adjustment.html

  3. Check something in your drive chain. A few years ago I had a bike where I got a notch in my front derailleur which chewed and snapped chains! So check front and back drive-train. Is your back wheel aligned correctly also?

  • 1
    I think its pretty hard to not align your back wheel correctly these days with vertical dropouts.
    – Batman
    Commented May 14, 2015 at 17:29
  • It's unlikely perhaps, . . but probably an obvious first thing to check, especially for those of us who tend to use ancient technology.
    – gaoithe
    Commented May 15, 2015 at 8:53
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    Actually, a skipping new chain on an old caassette is almost always due to sprocket wear. A stiff link can cause skipping, but it will only happen when the chain is in certain positions. A bent chainring tooth will skip when the crank is in a certain position. A bent derailleur will likely exhibit shifting problems, not skipping problems. To check, shift onto a middle cog and sight from behind the bike to ensure it is in the same plane as the cog. Wheel position issues don't typically result in skipping. I say typically because it's usually not accurate to say never. Commented May 31, 2020 at 1:48

If an old chain is jumping in all sprockets , it can only be the chain. (Sprockets dont wear at the same rate. I reckon it will be an incorrect new chain. My new kmc is too wide for my cassette. It does not bed down! Even though both cassette and chain are both nine speed and new. Very frustrating.


Typically you'll want to change your chain and cassette together, since they will both be worn, so it's not surprising that you're experiencing some slipping. It's also possible that your existing cassette is bent or damaged in some way rather than just being worn. I had an old XT 9-speed cassette where I somehow bent a few teeth to the right in the middle range, and even though it was barely noticeable, it made those middle cogs totally useless under load.

I assume you also bought a new chain that's the appropriate width for your rear cassette (9, 10, 11-speed, whatever). So if it's adjusted well and you have the right chain, I think it's safe to say that you'd benefit from also replacing the cassette.

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    Both be worn but not at the same rate. Cassette's usually last a couple of chains depending on length between changes.
    – AliGibbs
    Commented May 28, 2014 at 20:30
  • Rear cassette maybe last through 5 chains. Front rings maybe 10 chains. Some front rings might have alot less use than others. bicycles.stackexchange.com/questions/9158/…
    – gaoithe
    Commented May 14, 2015 at 16:50
  • You need to change the chain before it gets much wear in order to go through five of them before the cassette will need to be replaced. With a very expensive cassette, it might be worth running a mid-level chain and replacing it when it gets to 50% wear instead of 75% or higher. Chain wear rate has a lot more to do with the amount of dirt on (and in) the chain than how expensive it is. A fair weather road cyclist who sticks to pavement can get many, many times more mileage out of any chain than another who rides wet dirt. Commented May 31, 2020 at 2:03

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