Singlespeed & Fixed Gear - 15t freewheel Problem

So i finally found a 15t ACS freewheel to fix the gear ratio issues i was having with my conversion. I took my bike to my LBS to have them remove the old freewheel, install the new one, and adjust the chain length to fit the smaller freewheel.

Good news is, the smaller freewheel gives me the resistance i was hoping for! And it actually sounds way quiter (while coasting) than the new 16t freewheel i purchased with my new rear wheel. Bad news is, the chain/freewheel is making a loud noise when pedaling. sort of a grinding noise. at first i thought maybe the chain was just too loose (it doesnt look all that limp though) and that that was maybe causing some play, resulting in the noise. The noise ONLY happens when i am pedaling forward. it has also started to be punctuated by clicking.

After about 5 minutes of riding it, i went back to my LBS, and tried to describe to the mechanic the sound. He picked it up and spun the pedals (didnt put it on a lift) and said that it would probably take a bit of time for the chain to work with the new freewheel. I suggested a few things to check/change, but he didnt wanna adjust anything.

its been a couple days now, and the chain/freewheel is loud, noticeable.

Any ideas what could be the source of the noise? It's the same chain (minus a half-link) and just a new freewheel. So its gotta be one or the other or both. I'd hate to have to revert to the old 16t set up. Any ideas/suggestions?

Your chain is probably too tight. There should be enough slack that the chain can be moved up and down by about half an inch (if not more) and you should be able to see a slight catenary arc between the cog and the chainring.

How old is the chain? Sometimes using a very worn chain on new drivetrain components can be a problem.

Are you sure the chain tension isn't too tight? Give it a bit more slack and see.

Yeah, i dont think the chain is too tight. The chain itself is new. Probably less than 50 miles on it.

I'm sort of wondering if it could be the quality of the freewheel. I've heard some people complain about ACS freewheels being crap, but i just sorta chalked it up to there being someone everywhere on the internet talking **** about a particular component.

I have an ACS freewheel that makes a horrible clunking noise that seemes to get worse and worse. I ended up replacing it with a Shimano freewheel, which is working well so far.

It seems like most SS freewheels are a bit janky unless you are willing to drop some cash for a White Industries.

yeah, something about a $99 freewheel seems ****ed-up

yeah, something about a $99 freewheel seems ****ed-up

But until you have ridden one, or replaced 3-4 shimano/acs freewheels because they have no weather sealing, they may seem expensive.... but they really are not for what you get.

but the downside for you is their min # of teeth is 16 which does not help your goal. I just think its impressive you found a 15t freewheel.

Grinding sounds are more indicative of too tight of a chain.
You will get more of a "click-click-click" or "tick-tick-tick" if your chain is streched out and it not meshing well with your rear cog.

yeah, maybe its a RATTLE, more than a grind. I cant really differentiate whether its coming from the chain or the freewheel itself. gets louder the faster i pedal. cant tell if its the "chunk" that people complain about with crappy freewheels, or the way the chain is hugging the teeth of the freewheel. Maybe i'll have to get a new chain to test out the difference.

I am running this type of KMC chain. Do you think the different-style plates could be causing some problem with the 15-tooth freewheel?

http://ecx.images-amazon.com/images/I/412CDCTV6KL._SL500_AA280_.jpg

So this freewheel you got... is it new?

If it's old i'd say someone "repaired" it by flushing it out with lube... but didn't do a complete job.

yeah, something about a $99 freewheel seems ****ed-up

White industires Freewheels are nearly bulletproof. Like phil hubs, you literally are paying for quality. And that quality, lasts.

yeah the freewheel is new. but like i said, its an ACS 15t freewheel. People have said they are garbage (even though Harris Cyclery used to sell them, when they could stock 'em - and i usually trust their eye for quality). I dunno, maybe they are junk.

I'm sure White Industries freewheels are nice, but yeah, in this case they dont make 15t. I'm sure it would be nice to start with a fresh new frame and new wheels/hubs etc. Maybe i'll work towards saving up for all that, rather than fighting this struggle to make this bike what i want it to be.

Epilogue:
I ended up trying a different chain and that seems to have completely corrected the problem. The chain pictured above, has been described as "meaty", with larger links/plates. Apparently the 15t freewheel has more space between the teeth and the hub body. This combined with the meatier chain was resulting in alot of rattling, especially at higher speeds.

So, current lesson learned is ACS 15t freewheel is not (necessarily) a piece of crap.