OK I recently bought a chain measurer, found my chain was worn out which explains the slight skipping. I fitted a new chain (LX) and cassette (XT) but kept the unramped blackspire chainring I’m using.

It’s shifting and not skipping now but I’m hearing a kind of meshing noise under load. Is this because of chainring wear?

I have speculatively rotated the chainring 90 degrees but not tried it yet. If so, I guess I need another one.

What do you think?

think I know what you mean, but I can’t help
I get a noise that I’d call “meshing” when drivetrain is filthy – don’t know what the noise is (it just sounded expensive to me) but was one of the reasons I started SSing in winter

(ed) Having written “filthy drivetrain”, I wonder if it’s chainsuck (but in absence of any catching on the stays) and the noise is the chain being dragged off the chainring as it winds round

Yes, definitely. I’ve experienced exactly the same myself. The chainring’s effed & needs to go.

It depends Buzz – how worn was the chain that you replaced? If it was heavily worn, in some respects you may have been better off leaving the old chain on and replacing everything wholesale at a later date.

Its almost certainly due to spacing incompatibilities between the new, un-worn chain and the gaps between the teeth on the sprockets/chainring.

It may settle down as you prematurely wear the chain to the existing tooth profile of the worn rings.

If its shifting fine its unlikely to be a problem, other than a shortened life expectancy on the new chain (as compared to completely new drive-train) and the possibly some chain-suck in the clag.

Lift the rear & watch the chain entering / exiting the cassette & front chainring while you turn the pedals very slowly, & ideally get someone to feath the rear brake to simulate some pedal load. You’ll soon see any dodgy teeth / alignment issues.

Cheers all. I have a 36t ramped from my original double and bash SLX chainset so I’ll put that on.

OK how about this for a bodge…

I removed the worn single chainring, flipped it around so that the chain runs on the unworn edges of the teeth, and bolted it back on. With slightly longer chainring bolts because the normal recesses for the “nuts” are now against the insides of the cranks spider arms. Get me?

A quick spin and the noises have gone, indicating it was a meshing problem due to worn teeth. (Top advice chaps).

My worry is that flipped around, the nuts are not recessed into the chainring, the bolts might work loose. Is that a real risk?