replaced an acs claw 18t with a used 17t yesterday

rode it and discovered a curious noise yesterday... it took me a long time to localize the noise but now im certain its coming from the freewheel. its almost a pinging or a clinking noise thats emitted when i turn the pedal... when the wheel is spinning freely or when im coasting there is no noise.

i was thinking that it could be the misaligned engagement of the chain on the freewheel teeth but the chainline is pretty good (its a factory SS--not a convert). my other suspicion is that there are loose bearings inside the freewheel?

it would seem unlikely because the ACS Claw is unserviceable ... thusly the freewheel cannot be dismantled for some bearings to have gone bad... or maybe the grease is old causing the bearings to make noise moving against one-another? im not entirely sure... never done SS stuff before. if that is the case i just have to trash the freewheel and get another, right?

Could it be a damaged or failing pawl? Under load it exhibits this behavior (perhaps some slippage or floating) but when freewheeling it operates as would be expected.

i dont think that this behavior changes under different speeds or pedaling loads... i can hear it grinding up a hill just as i can with the bike upside down on my floor

"pinging" under load is usually a sign either that your timing is advanced too far, or that you need to run higher octane fuel.

wait, wrong interest. stop confusing me!

Oh yeah, fo' real, if your chain is worn out (stretched) it will make that noise on a new cog/freewheel when you pedal, as if you had worn in the old cog and the chain together, they wear in together, very slowly giving the teeth of the cog a slight ramp. If you are using a stretched chain on a cog without ramping on the teeth, it will clatter slightly against the edges of the teeth, until the teeth wear down (which doesn't take long with a older chain).

i advanced the timing from 15* to 17* but thats within limitations of 87 octane... and my engine will ****** the timing if it starts pinging, anyways. the improved throttle response and midrange power tells me its fine...


well, the chain came on the bike -- so both are about a month old. the freewheel is has a few more months of life on it because it came from a friends' bike. will the noise attentuate the more i ride the bike?

well shoot. then either they both just need to be broken in together, or i have no idea. if my idea was even remotely close, that it is an issue of chain/tooth matchup, you can usually check how well the teeth fit into the chain by putting the bike upside-down and turning the pedals very slowly, if the problem is external, it will often be visible. if its internal... is your chain too tight? that will cause weird things to happen with the bearings.
either way, im sure that riders more knowledgable than i will be responding soon.

yeah, i was thinking it had to do with the chain-teeth interface... but theyre all compatible stuff... the chainline was straight.. if i had to nitpick maybe its a fraction of a mm out of place so that cannot be the source of the problem. im scratching my head here

The teeth on the freewheel are not machined as well as they could be. There are rough spots on it from where it was cast. It was making noise on my bike when I had it, but it never slipped. Just a noisy freewheel, that is why I repaced it with a shimano.

ACS freewheels clunk. It's a fact of life. Lube the innards with some heavy oil or a 50/50 mix of grease and oil and it will quite it down for a while.

I have noticed the same kind of noise with a new ACS Freewheel. I cleaned it with some solvent and then oiled it; which seems to have stopped Clink/Ping noise as you decribed. The engagement seems slow with the ACS Freewheel.

What are the "better" alternatives to ACS Freewheels?

White Industries, but they are a lot of $$$. I must say though, they are sweet, running one now.

Just as an aside, have you checked your stackbolts? I've had pinging coming from there that I could have sworn was coming from elsewhere. The darn things seem to need tightening every week or so on my bike...