Broken chains - always on outer links?

[ColinJ]

I do a lot of riding on my singlespeed bike. If a chain snapped on my other bikes and I had to, I could shorten the chain. I can't do that on the singlespeed because the chain doesn't have a spare pair of links in it - it is the exact length that it needs to be. (The bike does not have horizontal dropouts so I can't just move the wheel closer to the front of the bike!)

I carry a spare length of chain so I could put that in if necessary, but it just struck me... I think that all of the 10-odd snapped chains that I have seen over the past 30 years snapped on the outer link of a pair. If that is always the case, I'd only have to use a quick link to replace a broken outer link on the singlespeed.

The question is... Have any of you (or anybody with you) ever snapped a chain at an inner link?

 

[si_c]

I do a lot of riding on my singlespeed bike. If a chain snapped on my other bikes and I had to, I could shorten the chain. I can't do that on the singlespeed because the chain doesn't have a spare pair of links in it - it is the exact length that it needs to be. (The bike does not have horizontal dropouts so I can't just move the wheel closer to the front of the bike!)

I carry a spare length of chain so I could put that in if necessary, but it just struck me... I think that all of the 10-odd snapped chains that I have seen over the past 30 years snapped on the outer link of a pair. If that is always the case, I'd only have to use a quick link to replace a broken outer link on the singlespeed.

The question is... Have any of you (or anybody with you) ever snapped a chain at an inner link?

If by snap you mean separate the links from each other, you can't as the inner plates are bounded by the outer plates. I suppose in theory you could find that the inner plates do fail and the link would separate like a paper clip but you'd need a fair amount of lateral movement and torque for that to happen, and I doubt you'd get that on a single speed bike. You'd certainly get a lot of drivetrain noise before the plate on the opposing side broke anyway so I would hope you'd stop and figure it out at that point.

 

[ColinJ]

If by snap you mean separate the links from each other, you can't as the inner plates are bounded by the outer plates. I suppose in theory you could find that the inner plates do fail and the link would separate like a paper clip but you'd need a fair amount of lateral movement and torque for that to happen, and I doubt you'd get that on a single speed bike. You'd certainly get a lot of drivetrain noise before the plate on the opposing side broke anyway so I would hope you'd stop and figure it out at that point.

I mean literally break, like these outer plates did...

I don't think that it is very likely for the inners to go. Obviously, for failures like those above it would be (and was!) less than a 5 minute job to replace with a quick link***.






*** Unless you are foolish enough to not carry any quick links, in which case it could be hours to get to somewhere selling them, or a train or taxi home!

 

[geocycle]

It is unusual for inner links to beak but not unknown. Here is a thread I started on the CTC forum in 2008 with some useful replies. I’m not sure what happened here but I do agree the chain was filthy. Note it was on my rohloff bike.
https://forum.cyclinguk.org/viewtopic.php?p=155939&hilit=Chain#p155939

 

[T4tomo]

sample of 3:
2 outer plates in succession in 5 minutes!!
1 pin failure (I think) so your repair with quick link still holds

@geocycle 's looks like it was subject to alien attack

 

[ColinJ]

It is unusual for inner links to beak but not unknown. Here is a thread I started on the CTC forum in 2008 with some useful replies. I’m not sure what happened here but I do agree the chain was filthy. Note it was on my rohloff bike.
https://forum.cyclinguk.org/viewtopic.php?p=155939&hilit=Chain#p155939

Interesting... (And VERY odd!)

As well as quick links, I will continue to carry a short length of spare chain, just in case, but I would be very surprised if an inner link failed me.

 

[Sharky]

singlespeed

I suspect that the risk of breaking a chain with a SS is very low. You don't apply any sideways force as you do with FD & RD'S.

 

[presta]

I mean literally break, like these outer plates did...

View attachment 656668

View attachment 656669

I don't think that it is very likely for the inners to go. Obviously, for failures like those above it would be (and was!) less than a 5 minute job to replace with a quick link***.






*** Unless you are foolish enough to not carry any quick links, in which case it could be hours to get to somewhere selling them, or a train or taxi home!

The inner plates are stronger at the hole because they have the flange on the inside that the rollers run on.

 

[ColinJ]

I suspect that the risk of breaking a chain with a SS is very low. You don't apply any sideways force as you do with FD & RD'S.

I agree, but I still managed to do it!

That's interesting... As I mentioned above, I bought a bag of generic 8-speed quicklinks from China. I used one of them to repair the chain on my singlespeed bike recently. Fortunately, it fitted ok.

The chain broke just as I was about to stand and sprint up a short local hill. If it had happened even 1 second later it could have had painful consequences, but I was lucky - I just coasted to a stop.

The broken link...

View attachment 527007

The inner plates are stronger at the hole because they have the flange on the inside that the rollers run on.

They certainly look stronger to me, and I don't recall ever seeing a broken one!

 

[Dogtrousers]

Simple solution is to carry a few links of chain as well as a couple of split links (and a chain tool, of course). That should cover all eventualities.

 

[ColinJ]

Simple solution is to carry a few links of chain as well as a couple of split links (and a chain tool, of course).

Do keep up at the back!!!

As well as quick links, I will continue to carry a short length of spare chain, just in case, but I would be very surprised if an inner link failed me.

 

[Dogtrousers]

Do keep up at the back!!!

So ... why have this thread?

What next?
I've been wondering. Could a thorn get through my tyre and puncture my inner tube?
To protect against this eventuality I have taken to carrying a spare inner tube.

 

[ColinJ]

So ... why have this thread?

Because I was simply curious to know...

Have any of you (or anybody with you) ever snapped a chain at an inner link?

 

[silva]

Just put a motorcycle chain on it, the frame will separate before the chain.

 

[Ajax Bay]

Answering the OP, no - 'snapping' always outer link plate or pin insertion fail so I think your deduction is entirely reasonable. No need to carry a spare link; just carry a chain tool and a quicklink.