jgedwa

Putting together a bunch of leftover parts onto an old MTB frame.

I have a NOS Suntour 12 tooth - 1/8 cog. For a chain I have a cheapo Bell BMX (but I suspect it is a rebranded KMC).

The chain is VERY noisy, and I can see the chain fighting to sit down in the gaps on the cog as it turns. I can easily see the chain throbbing up and down when spun quickly.

Chain tension seems not to be the problem; the chatter is there at high and low tension.

Chainline does not seem to be the problem. I have it dialed in perfectly. In any case, I tinkered a bit to move it inboard and outboard a smidge, and there was no change.

jim

nathbdp

Lube that shiz up reaaaaaaaaly good yeah...

jgedwa

it is a brand new chain, so it has the factory lube all through it. But for good measure, I oiled it anyway. No difference.

mihlbach

I doubt that its a lube problem. Even without any lube, the chain might be noisy, but it should not have trouble engaging with the teeth of the cog. The symptoms you are describing sound like putting a new chain on a worn cog. Is the cog new?

jgedwa

new (NOS) cog, new chain

wetigers

do you have a lockring on the hub? 12t cogs require lockrings suited to them.

ex: https://cgi.ebay.com/SUNTOUR-12t-Trac...QQcmdZViewItem

jgedwa

it is a suicide hub. (yeah, I know, I know). There is a BB ring on it, but there is clearance between it and the chain. That was my first thought, and so I have watched it go around and around to be sure it does not hit anywhere.

Seems like I have heard some people say that some cog brands are noiser than others. And this is not one of the usual cog brands (Suntour), so I wondered if someone had ever used one and noticed drivetrain issues.

jim

San Rensho 

Is the chain line good?

edit-Oops, reread your post.

schwinn

I just had this same issue last night. I had rode through the rain, nothing serious, but long story short there were tons of pieces of dirt/mud in the links somehow. I hosed the chain down full blast then re lubed it up and it seems to be ok.

buro9

Sounds like a worn sprocket.

You mentioned a new chain - if you have a new chain and old sprocket, it may well be as simple as the sprocket being worn.

Do you have a newer sprocket just to put on and test whether it is that?

jgedwa

the cog has never been on a bike. It is new old-stock, but it has never been used before now.

And it is not simply a lube problem. Brand new chain, and before taking it out at all, the noise was there on the repair stand when I spun it. I did lube it again, but made no difference. Anyway, it is clear to my eye that this is more than a lube problem; the chain just does not seem to want to sit down in the cog teeth.

Maybe it will wear in?

nexus6

Double check both the chain and cog sizes, that they're 1/8 and not 3/32?

mihlbach

I had a very similar problem with a surly cog and an izumi chain, both 1/8". I switched to an EAI cog and the problem went away more or less. The Izumi chain was still rough with the EAI cog, but not nearly as bad as with the Surly cog. Some parts are just finicky I suppose. I have since switched to KMC chains and they have worked smoothly with every cog I've ever tried.

sivat

Some cogs and chains just don't play well together. I had similar problems with a wipperman chain and soma cog. I switched to an EAI cog and everything was copacetic. I would suggest a new chain, since you are using a good quality cog. I also agree with nexus6, it could be a 3/32 chain and 1/8 cog.

jgedwa

Rear cog and chain are 1/8, chainring is 3/32. The noise is coming from the rear cog.

Like the last couple of posters, I tend to think that some cogs and chains just do not fit well together.

jeac

after reading the thread i realize your problem isn't your chain, but i just feel the need to say that

triflow is the best stuff in the universe.

jgedwa

Actually, it is practically dripping triflow as we speak. Lube is not the problem. Lube does not change the profile of the teeth on the cog.

jeac

i acknowledged that your chain is not your problem

i just wanted to express my love for triflow

hairlessbill

I have almost the same setup and the same problem. Is there a chart of best cog/chain/chainring for quiet drivetrains? Or just combinations to avoid?

blickblocks

I have the same issues. New cog, new chain, but they don't seem to like each other. Maybe it has to do with the chainring...if the chainring is worn then the pitch becomes larger, which would make the cog and ring out of sync.

diff_lock2

Maybe the chain is just too tight?

nexus6

Sometimes anything new on a drivetrain can make it noisy until everything beds down a bit. I had a bit of noise when I changed my chainring last time, but it settled down.

operator

Get rid of the 1/8 stuff and switch to 3/32. I guarantee your noise level will be lower.