Help me identify what's causing the tink

[NHAero]

Originally Posted by Carbonita

I fixed the same issue on Friday for a buddy after he'd taken it into his shop several times, and changed pedals. Anti seize and proper torque seat clamp and rails.

Originally Posted by tellyho

Oh, if you don't hear it standing: saddle rails, seatpost clamp, seatpost lube?

What would cause the sound to disappear when in the 11 through the 21T cogs?

[prototoast]

Did I miss what fd you are using?

[Hilltopperny]

The last time I had this happen the cassette needed a bit more tightening down. It felt fine, but a little more torque and the noise was gone!

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[Carbonita]

Seat loading dependent on gearing and crank angle.

Originally Posted by NHAero

What would cause the sound to disappear when in the 11 through the 21T cogs?

[Peter P.]

I'm currently having a similar problem which is very close to NHAero's-the "tink" is in sync with crank rotation and appears roughly when the right crankarm is in line with the front derailleur cage.

I've checked everything for clearances and there's nothing touching.

My next course of action, which perhaps NHAero can try as well, is what I tried today- I thought maybe there is something on the large ring's teeth causing the chain to hang up oh so slightly before settling into the tooth as the chainring came around to the right position.

I did find some burrs on a few teeth of the large ring (It's a virtually new TA chainring) directly behind the crankarm. I gently gave the questionable teeth a few strokes with a file. I have yet to ride the bike to see if I was successful.

[NHAero]

Originally Posted by prototoast

did i miss what fd you are using?

r8000

[NHAero]

Originally Posted by Peter P.

I'm currently having a similar problem which is very close to NHAero's-the "tink" is in sync with crank rotation and appears roughly when the right crankarm is in line with the front derailleur cage.

I've checked everything for clearances and there's nothing touching.

My next course of action, which perhaps NHAero can try as well, is what I tried today- I thought maybe there is something on the large ring's teeth causing the chain to hang up oh so slightly before settling into the tooth as the chainring came around to the right position.

I did find some burrs on a few teeth of the large ring (It's a virtually new TA chainring) directly behind the crankarm. I gently gave the questionable teeth a few strokes with a file. I have yet to ride the bike to see if I was successful.

The imperfect teeth as a cause seems plausible in the sense that chain angle could affect whether a burr or similar would make noise. What mitigates against this is that this crankset was on another bike previously without this issue.

I should have said that this is the bike that had the twisted portion of the chain
that I straightened. Again, if the periodicity matched one chain rotation instead of one crank rotation I'd be more suspicious of the chain as a cause.

[Mark McM]

If the 'tink' is periodic with the crank rotation, that sure suggests it is related to the crank or BB, or something adjacent to them. On the other hand, it only occurs in certain sprocket, that would suggest it is cassette related.

Since you've checked out the crank bolts, pedals, and front derailleur, what about the BB? I find that when a BB starts going bad, or if there insufficient pre-load on the BB, it may make a 'tink' or 'creak' sound as pedal force is applied at the start of the power stroke. A BB30 crank uses spacers and a wave washer for BB pre-load, have you checked if there is enough pre-load? Do you have another BB you could try?

As the sound only occurs in the large sprockets, is it possible that the offending sprockets are all mounted on the same spider carrier? If the spider is cracked, it could make a sound when pedal force is applied at the start of the power stroke.

[camelbackkid]

Does it occur in the same fashion in the repair stand, or only or differently when riding?

[helldriven]

As mentioned above, I've had issues with Bottom Bracket and seat post/seat rails for intermittent ticking. I am sure you have already checked but are your pedals on tight?

[eddief]

loose spoke nipple? maybe your brain thinks it has the correct variables but maybe it really doesn't.

[NHAero]

Originally Posted by camelbackkid

Does it occur in the same fashion in the repair stand, or only or differently when riding?

Can't hear it in the stand, so I think it requires some power to be exerted.

[NHAero]

Originally Posted by helldriven

As mentioned above, I've had issues with Bottom Bracket and seat post/seat rails for intermittent ticking. I am sure you have already checked but are your pedals on tight?

I think so, especially since I have tried two sets and switched back to the first set, with consistent sound happening.

[Ralph]

I have had that problem before when the next to smallest cog wasn't on right and then tightened by lockring. Cog could move slightly under load.

[NHAero]

Originally Posted by Mark McM

If the 'tink' is periodic with the crank rotation, that sure suggests it is related to the crank or BB, or something adjacent to them. On the other hand, it only occurs in certain sprocket, that would suggest it is cassette related.

Since you've checked out the crank bolts, pedals, and front derailleur, what about the BB? I find that when a BB starts going bad, or if there insufficient pre-load on the BB, it may make a 'tink' or 'creak' sound as pedal force is applied at the start of the power stroke. A BB30 crank uses spacers and a wave washer for BB pre-load, have you checked if there is enough pre-load? Do you have another BB you could try?

As the sound only occurs in the large sprockets, is it possible that the offending sprockets are all mounted on the same spider carrier? If the spider is cracked, it could make a sound when pedal force is applied at the start of the power stroke.

I'm trying a different wheel with a different cassette tomorrow. Great idea about the spider carrier, though there are two, each with three cogs, and the sounds seem to be on only two of the three cogs on the 21-23-25 one.

BB is possible and I have a set of Praxis Zayante arms and BB that will swap in for the SRAM at some point, so I'll see if it's not solved by then.