Snapped chain on hub geared bike - what causes it

[gbb]

It looks like the plates have departed on a factory rivetted link, not the one where OP joined it., so it's reasonable to assume its a cheap, not so cheerful, poorly made chain.

It's a bit sobering to think as a kid, I'd punch out a rivet on a chain, do what I needed then reassemble using the same pin and peen over the rivet with a hammer . Luckily I never had one fail on me.

 

[Drago]

3 causes -

Faulty materials and/or workmanship.

Wear.

Combination of the above.


You'll likely never know for sure which caused yours to go.

May was well lock the thread now

 

[alicat]

Oi, you leave my thread alone. It's got to three pages and I'm confident that it might make four with a fair wind.

 

[rualexander]

Small stone or something gets stuck to chain and forces the sideplates apart as the chain engages the sprocket or chainring?

 

[alicat]

Thanks, @rualexander. That's the only cause I can probably rule out since the chain is enclosed in a chaincase and I didn't find any foreign object when replacing the chain.

 

[Pale Rider]

I'm surprised it broke - a hub gear chain in a chain case barely wears at all.

It's always in perfect alignment and the case keeps dirt and grit away.

There was a bike maker, might have been Sun, who designed their enclosed chains to run in a shallow oil bath.

Those chains lasted literally decades.

 

[alicat]

The chaincase was only in place for the last year of the chain's life so that the chain did get some dirt etc beforehand.

 

[Pale Rider]

The chaincase was only in place for the last year of the chain's life so that the chain did get some dirt etc beforehand.

You were still unfortunate to have one break because the naked chain still runs in perfect alignment.

A lot of breaks seem to happen when the chain is derailed when changing gear.

The higher chain line on a hub gear bike also keeps the chain cleaner - up out of the way of the worst road dirt.

Now you've sorted it I doubt you will be replacing it again for a long time.