Chain continually breaking

tangotonyb

I had issues with slipping gears so I replaced my rear cassette and the central cog at the front last summer, together with a new chain. The jockey wheels were quite worn and I tried to order some online to replace, but everywhere was out of stock at the time, so I nicked the 2 off my road bike which I wasn't using.

Since then, my chain has gone half a dozen times - I actually replaced it again, but the new one went on the second time out. Note - before I changed everything, the original chain had only gone once in 7 years of use. When it goes incidentally, invariably it's not under any load - i.e. it doesn't go on a hill or when accelerating hard. It's normally just trundling along on the flat.

When I examine the chain, the side pieces are all slightly curved, like the teeth the chain is passing over are slightly too wide for the chain and over time are pushing the side pieces out in each link until eventually one side comes off the pin. The front cog is a like-for-like replacement of original, and the cassette and chain were recommended on here, so that leaves the jockey wheels....

Are jockey wheels different for road/mountain bikes such that they could cause this effect?

dtaylor243

Have you been cross chaining, riding with the chain on the big chain ring and small rear cog?

pblakeney

dtaylor243 said:

Have you been cross chaining, riding with the chain on the big chain ring and small rear cog?

That is the direct opposite of cross chaining. 🤔

Mad_Malx

I cannot imagine that the jockey wheels are damaging the chain. They're the softest bit in the drivetrain.

masjer

If it's a Shimano chain, is it breaking at the joining pin you've installed.
i.e. is the pin installed correctly?
Have you got the correct chain length and not just installing a full-length chain from the box/bag?

First.Aspect

Could be the chainrings damaging the chain, eg it there is a damaged tooth, bent sideways or something like that.

Could be breaking where you are joining the chain. If you using a joining pin it is easy to get that wrong. (If you are using a quick link, it isn't going to be this.)

Unlikely I know, but if you are using old chain rings that are too wide, e.g. 10 speed rings with an 11-speed chain, that might eventually damage the chain.

masjer

First.Aspect said:

Could be the chainrings damaging the chain, eg it there is a damaged tooth, bent sideways or something like that.


Unlikely I know, but if you are using old chain rings that are too wide, e.g. 10 speed rings with an 11-speed chain, that might eventually damage the chain.

An 11 speed chain is fine on 10 speed. The inner chain width is the same on 10 and 11 speed chains.

First.Aspect

masjer said:

First.Aspect said:

Could be the chainrings damaging the chain, eg it there is a damaged tooth, bent sideways or something like that.


Unlikely I know, but if you are using old chain rings that are too wide, e.g. 10 speed rings with an 11-speed chain, that might eventually damage the chain.

An 11 speed chain is fine on 10 speed. The inner chain width is the same on 10 and 11 speed chains.

Whatever - there are combinations where it isn't. I doubt it is that anyhow. Also, if it was a damaged chainring, you'd probably hear it tick each crank revolution and the OP hasn't mentioned this.

My guess is it is where the continually breaking chain is being rejoined.

masjer

First.Aspect said:

masjer said:

First.Aspect said:

Could be the chainrings damaging the chain, eg it there is a damaged tooth, bent sideways or something like that.


Unlikely I know, but if you are using old chain rings that are too wide, e.g. 10 speed rings with an 11-speed chain, that might eventually damage the chain.

An 11 speed chain is fine on 10 speed. The inner chain width is the same on 10 and 11 speed chains.

Whatever - there are combinations where it isn't. I doubt it is that anyhow. Also, if it was a damaged chainring, you'd probably hear it tick each crank revolution and the OP hasn't mentioned this.

My guess is it is where the continually breaking chain is being rejoined.

Tis true about chain width. 10 and 11 speed Chainrings are the same width too.
It actually makes sense to use an 11 speed chain on a 10 speed set up as the chains generally last longer, believe it or not.

First.Aspect

masjer said:

First.Aspect said:

masjer said:

First.Aspect said:

Could be the chainrings damaging the chain, eg it there is a damaged tooth, bent sideways or something like that.


Unlikely I know, but if you are using old chain rings that are too wide, e.g. 10 speed rings with an 11-speed chain, that might eventually damage the chain.

An 11 speed chain is fine on 10 speed. The inner chain width is the same on 10 and 11 speed chains.

Whatever - there are combinations where it isn't. I doubt it is that anyhow. Also, if it was a damaged chainring, you'd probably hear it tick each crank revolution and the OP hasn't mentioned this.

My guess is it is where the continually breaking chain is being rejoined.

Tis true about chain width. 10 and 11 speed Chainrings are the same width too.
It actually makes sense to use an 11 speed chain on a 10 speed set up as the chains generally last longer, believe it or not.

You'll have to explain that to me.

masjer

Contrary to what sounds logical, each incarnation of chain from 8,9,10,11,12 speed, keep getting more wear resistant. 12 speed lasts far longer than 8.

masjer

First.Aspect

Thanks, I uunderstood what you meant by 'lasts longer'. It was more the 'why' I was curious about.

masjer

I'd guess that as the pins and plates etc have got narrower/thinner, the hardening process has got better- so more wear resistance. Maybe better materials, coatings and quality control too?

dtaylor243

pblakeney said:

dtaylor243 said:

Have you been cross chaining, riding with the chain on the big chain ring and small rear cog?

That is the direct opposite of cross chaining. 🤔

Yes quite right, brain cross chained.
But I think for the OP to experience so many chain breaks the drivetrain which I assume is 9 speed or lower must be making a horrid noise.
Best thing if things don't sound and feel right just take it to a bike shop.

tangotonyb

First.Aspect said:

Could be the chainrings damaging the chain, eg it there is a damaged tooth, bent sideways or something like that.

Could be breaking where you are joining the chain. If you using a joining pin it is easy to get that wrong. (If you are using a quick link, it isn't going to be this.)

Unlikely I know, but if you are using old chain rings that are too wide, e.g. 10 speed rings with an 11-speed chain, that might eventually damage the chain.

Thanks.

I was hearing ticking sometimes when I rode - particularly uphill. I figured my rear gears needed realigning so I tweaked them and the tick went away.

The chain is a Shimano, so jointing pin. I'm pretty sure it was installed correctly - it wouldn't explain the bulging on all links anyway. I'll take a photo and post it so you can see what the chain looks like. I'll try and look for a damaged tooth too.

me-109

Is the 'bulging' not just the profiling of the chain links, designed to aid shifting?

Mad_Malx

masjer said:

I’m intrigued. What is this graph showing - and what is the source?

focuszing723

Mad_Malx said:

masjer said:

I’m intrigued. What is this graph showing - and what is the source?

And perhaps the biggest takeaway from all of this testing is that no matter how durable a chain is, the lubricant you use will play the most critical role in drivetrain durability. Kerin toasted an endless number of chainrings and cassettes in his testing, and basically, any chain that lasted over 2,500 km ripped through the cassette and chainrings through nothing more than abrasion from the gritty lubricant.

As always, run a good lube and keep your drivetrain clean – that’s the real trick to getting the most value and performance from your drivetrain components.

https://cyclingtips.com/2019/12/the-best-bicycle-chain-durability-and-efficiency-tested/

And this is the conclusion.

mully79

Mad_Malx said:

masjer said:

I’m intrigued. What is this graph showing - and what is the source?

The graph is showing that a £50 chain only lasts 3 x longer than a £10 chain...

First.Aspect

It is better to be red than blue, most of the time.

This is correlation not causation. You would get the same graph with today's 11sp da, ultra, 105 etc.

Mad_Malx

focuszing723 said:

Mad_Malx said:

masjer said:

I’m intrigued. What is this graph showing - and what is the source?

And perhaps the biggest takeaway from all of this testing is that no matter how durable a chain is, the lubricant you use will play the most critical role in drivetrain durability. Kerin toasted an endless number of chainrings and cassettes in his testing, and basically, any chain that lasted over 2,500 km ripped through the cassette and chainrings through nothing more than abrasion from the gritty lubricant.

As always, run a good lube and keep your drivetrain clean – that’s the real trick to getting the most value and performance from your drivetrain components.

https://cyclingtips.com/2019/12/the-best-bicycle-chain-durability-and-efficiency-tested/

And this is the conclusion.

Thanks. The badly labelled y axis on the figure above was confusing me.

focuszing723

No probs, yeah. I don't know what to make of it really and it's a fair point Mully79 makes.

I've never had a chain snap on me.

pblakeney

focuszing723 said:

I've never had a chain snap on me.

Lightweight. 😉

focuszing723

More middle weight, but yeah, entirely probable.

Charlie_Croker

Like @me-109 say's up this thread...



From left to right:
Campagnolo 11 speed, SRAM 10 speed, Shimano 9 sp, SRAM 6/7/8 sp, old 5 speed, 1/8″ single speed chain

JBA

What speed groupset are you running?
If you are running an older 6 or 7-speed groupo but fitting an 11-speed or 12-speed chain that could be your problem.

MattFalle

pblakeney said:

focuszing723 said:

I've never had a chain snap on me.

Lightweight. 😉

i don't think they make chains, just wheels and frames, yah?