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How to tell when chainring is worn? Pic inside

11K views 13 replies 8 participants last post by  c8stom  
#1 ·
I have a narrow wide chainring (Race Face, 40 tooth) on my cross bike and I think it might be nearing replacement time. It is skipping under load but only really high load (like standing on a climb steep enough to be in the easiest 2-3 gears).

In case it is related I wanted to include that I just put a power meter on this bike and I had to adjust the derailleur afterwards. The crank uses a proprietary crank spindle which needed a different combination of spacers than the stock one to fit right so I think the chainline may be a hair different. 2 clicks clockwise on the barrel adjuster got the derailleur perfect so any difference was a small one. Just wanted to include this in case it was relevant.

The chain is not stretched whatsoever and the cassette is in great shape according to my Rohloff cassette wear indicator (both have <500 miles, chainring is around 2k miles). See pic. The black finish on the teeth only lasts a few rides so that isn't really an indication of wear. I've worn 30T Race Face rings in <500 miles so if this one is cooked at 2,000 miles I'm fine with that. None of the squeaking noises I've heard with worn rings in the past though.


 
#2 ·
It doesn't look terribly worn in that pic to me but if you're positive it's skipping on the chainring I would replace it asap regardless of how it looks. Actually I would probably put a new chain on first just to confirm the problem because if I bought a new ring I'd want to start fresh with a new chain anyway.
 
#3 ·
I'm not certain that it's coming from the chainring, it feels like it's coming from the cassette.

None of the teeth are bent on ring or cassette, the freehub ratches are fine (DT swiss hub), chain/cassette are low miles. It occurred to me it might be the chainring since I've toasted RaceFace MTB rings, albeit with a lower tooth count, in 500 miles and this one has almost 2,000.
 
#4 ·
I've worn 30T Race Face rings in <500 miles
This is difficult to believe. User error, most likely.

It's your cassette. Or your RD attachment bolt has backed out a bit. Or you have a damaged chain link/ stiff pin. Or your shift housing is gummed up. Or it was installed with goofy chainline. Tough to diagnose over the internet.

Chainrings don't skip, and that one doesn't have any real signs of wear.
 
#5 ·
Tons of threads on here of people toasting XX1 or RaceFace rings with not a lot of miles on them, some people reporting 250-300 miles. Mine weren't totally shot, but they were starting to creak/squeal. Just checked my maintenance log and Strava to get exact mileage. Bike has 1683 miles. It's on the 2nd cassette (replaced about 500 miles ago), 3rd chain (replaced about 100 miles ago), and 1st chainring.

Concerning chainline, I previously used the 10mm (?) SRAM spacer (pic below) plus one 1mm spacer. I ditched the 1mm spacer when installing the power meter so if anything the chainline would be better for the gears I'm now having issue with.

 
#7 ·
This chainring is in a perfect working order. If the chain is new, then I suspect that either you have some sort of adjustment issue, which causes the rear mech to ghost shift momentarily, which gives this skipping sensation.

This may be due to stiff chain link, cracked/flexy frame, bent hanger or what have you - difficult to judge over the internet.
 
#8 ·
I'd also check the rear derailleur hanger alignment to be sure it's straight. And with a proper tool, not just line-of-sight. I've had hangers that were slightly bent and when really torqueing the drivetrain, the combination of the bent hanger and frame/drivetrain flex caused the chain to not be completely "on" the cog or cause a little ghost shifting. Also inspect the derailleur to be sure it's not bent of damaged in any way. Good luck.
 
#10 ·
Rear derailleur hangar is straight (with the tool--Park DAG-2.2). Derailleur is cool too.

Took it apart today and the freehub ratchets are all good, freehub body isn't cracked, cassette is torqued on properly, chain length is correct, no bent teeth on ring or cassette. Can't think of what else it is.
Did you check your chain wear how old is the chain I've gone to .75% on a XX1 chain in less than 200 miles.
PM me if you want to check derailleur hanger I have a Park tool Dag-2 I'm in Roseville also have the CC-2 Park CC-2 Chain checker.
Your chain ring looks fine
Yeah I burn up chains on this bike around 600 miles during the bad weather season. This chain went on when the weather dried out. Checked the chain stretch with Park CC-3.2 and with ruler, zero stretch. Thanks for the offer with the tools.
 
#9 ·
Did you check your chain wear how old is the chain I've gone to .75% on a XX1 chain in less than 200 miles.
PM me if you want to check derailleur hanger I have a Park tool Dag-2 I'm in Roseville also have the CC-2 Park CC-2 Chain checker.
Your chain ring looks fine