Broken Chain! I’m a complete amateur

[Jaxof933121]

Hey, hoping to get some advice. I’m a complete and utter amateur when it comes to cycling but love doing it. My chain recently snapped and I have no idea how to fix it and don’t want to spend out £24 to get it done when it seems an easy fix. Can anyone please advise? Thanks

[Jdsk]

Welcome

Two great resources:
https://sheldonbrown.com/chains.html
https://www.parktool.com/en-int/blog/re ... a%5B%5D=50

You need to decide whether to repair or replace the chain.

You need to check the wear on the chainrings and the rear sprockets.

Chains now come in various widths and you need to use the right one for your bike.

Magic links are now available that enable you to join the ends of chains without the traditional tool.

Jonathan

[Airsporter1st]

Fixing it yourself is relatively easy, but that’s curing the symptoms and not necessarily the disease. You need to know why it snapped and take steps to ensure it doesn’t happen again.

[MikeF]

Note - first post.

[richardfm]

Fixing it yourself is relatively easy, but that’s curing the symptoms and not necessarily the disease. You need to know why it snapped and take steps to ensure it doesn’t happen again.

Any suggestions as to what might have caused it?
I was checking over one of my bikes the other day and found a broken side plate on the chain. I will replace the chain before riding it again so won't suffer from a broken chain. I would like to know what caused it, but have no idea how to diagnose the cause

[mattsccm]

I would start by looking at the rest of the gearing set up. Is something bent? Stick a new chain on and rotate.
You say that you are new to this? Is the damaged link one of those quick release ones? Just a thought. Might be able to just get another if so.

[Brucey]

......found a broken side plate on the chain ...... I would like to know what caused it, but have no idea how to diagnose the cause

chains are pretty reliable considering they are no stronger than their weakest link etc. I have ridden hundreds of thousands of miles and despite being no shrinking violet when it comes to stomping hard on the pedals, I have only once suffered a broken chain. To this day I don't know if it was the link I 'made' with a chain tool or not, but it might have been. Since then I have studiously avoided chain tool use on 9s and higher chains, except for shortening them.

Chain manufacturers have been walking the tightrope of reliability for a few years now; every iteration (the more widespread use of 12s being the latest) requires the chain to be narrower and made of stronger steel with thinner side plates. You would be forgiven for thinking that they just can't carry on doing this indefinitely and you would be right. Each iteration demands a stronger, more expensive steel than the last, and the overall reliability of chains is probably getting worse.

To their credit,chain manufacturers get it right far more often than they get it wrong but get it wrong they sometimes do. What you cannot see or know is what levels of residual stress in a chain (eg. from the riveting process) or whether the steel is now susceptible to SCC or not. There is something of a 'leap of faith' involved here; you hope that the chain manufacturers have done their homework. So you can improve your odds of being happy by being sure of your chain; there are an awful lot of fakes out there, and if you buy on price alone you are quite likely to end up with one. The chain lubricant you use makes a difference too; IME a chain that manifests any signs of corrosion is also more likely to break.

[mig]

what 'sort' of broken chain?

you were riding along and it quietly separated somewhere along its length?

it physically snapped in use?

there was some sort of malfunction of the gearing resulting in a tangled chain, rear mech, chainset type of combo and the chain came apart in the resultant melee?

[colin54]

I'll bite Brucey, SCC meaning; stress....?
Would cross-chaining on triples increase the likelihood of breakage ?
It might be useful in assisting the original poster if he tells us how many sprockets he has on the rear wheel, and if triple chainwheels at the front, if a derailleur bike.

[531colin]

Stress corrosion cracking.
I am indebted to Brucey for that information, as well as so much else.
Also get SCC in alloy, eg hub flanges, as I understand

[531colin]

Unless I made it up, wasn’t there an episode years back when a particular type or make of chain used to get cracks in the sideplates radiating out from the rivet?
Wrong sort of steel or hardening process?

[colin54]

Thanks Col

[richardfm]

Unless I made it up, wasn’t there an episode years back when a particular type or make of chain used to get cracks in the sideplates radiating out from the rivet?
Wrong sort of steel or hardening process?

That rings a bell with me.
I'm away at the moment but when I get home and replace the chain (it's on a 2x10 speed) I will inspect it. I don't remember if it has a quick link or if I used a chain tool, but that might be relevant

[531colin]

These days I don’t join any chain with a chain tool, even 8 speed…..always a magic link.
My chain tool usually has several “necklaces” round the pin, these are the “peened over” rivet ends which come off when you push the rivet out.

[NickJP]

Unless I made it up, wasn’t there an episode years back when a particular type or make of chain used to get cracks in the sideplates radiating out from the rivet? Wrong sort of steel or hardening process?

I've seen it on a few chains in the past few years. Here's one - this is a KMC, but I've also seen the same problem with other brands of chain.