Chain not meshing with chainring properly?

[bltamil1]

I’ve recently replaced a chainring that was visibly worn, and now have an issue where the chain doesn’t seem to mesh properly with the ring, and the chain is sitting ‘proud’ of the ring for about 40% of the circumference.



I didn’t replace the chain, and this is probably the problem I guess, but I can’t work out why that would be!

Can anyone offer an explanation of what I’ve got wrong here?

Edited to add that the whole drivetrain does seem to be unusually noisy! It’s a full Ultegra mechanical set up, compact chainring on the front, 11-28 cassette on the back.

[jfdi]

Is that a new chainring? Zooming in those teeth look knackered

[stargazer30]

Get a chain gauge for £5 and check the chain. If it’s stretched badly it won’t mesh. If it’s that bad the cassette will probably be knackered too. Always replace your chains at 0.5 to 0.75 stretch to protect your chain rings and cassettes from excess wear.

[Crippo]

You need to change your chain. Its worn and doesn't fit a new chainring.

You may also find the cassette is also knackered and when you put a new chain on it will jump on the cassette.

This is why changing your chain often is important as you wear out the far more expensive chainring and cassette.

[bltamil1]

Thanks gents, looks like a new chain is in order. The cassette and chainring are both new, I thought I changed the chain recently too, but now I think I was probably imagining that!

[bltamil1]

jfdi said:

Is that a new chainring? Zooming in those teeth look knackered

Haha, yes it is! You did make me wonder whether I had somehow put the old one back on and tossed the new one by mistake!

[mooseracer]

I might be daft and/or wasteful but I'd never change a cassette or chainring without doing the chain as well

[WPA]

New chain required

[bltamil1]

Thanks all. I put a new chain on it and it’s all sorted. The old one must have done a lot more than I thought!

New HG-11 chain and a tweak of the rear derailleur and it’s purring like a kitten again.