hyhuu

On my 53/39 chainring, the large one is absolutely quiet while the small one is quite noisy. Nothing is rubbing and it doesn't look like there is any significant wear either. The loudness (it's like a whzzz grinding) is directly proportional to the pressure apply to the crankset - 3-o'clock being the loudest. So what gives? Thanks.

FBinNY 

You didn't say new or old, but on used stuff it could simply be wear related. As chainrings and chains wear the pitch becomes mismatched slightly so you get more of the whirring sound characteristic of chain drive. It doesn't take much wear to make a difference so you won't see it easily. Since most people don't use the rings equally it's easy for the two rings to be mismatched.

BTW- it isn't always the worn ring that's noisier. As the chain stretches it can run quieter on the more commonly used ring and noisier on the newer one.

BTW- this all presumes that you're right that nothing is rubbing anywhere.

bradtx

hyhuu, Just a guess, but the chain's maybe rubbing against the FD's cage.

Brad

hyhuu

Thanks. I'm confident that there is no rubbing (I checked and rechecked). Also the noise is consistent regardless of what gear I'm in. The chainring is definitely old as I bought the bike used. The chain and cassette are brand new. Your explanation makes sense as I noticed the noise with the new chain. I'm looking for the shark-tooth profile on the chainring but saw none so I assumed there is no significant wear.

Shimagnolo

Last spring, right after putting a new chain on a triple crankset, I had a *lot* of noise on the small ring. Careful examination revealed the teeth had worn to where they were just slightly hooked, and *attempting* to suck the chain up toward the FD, but there was enough tension in the chain to forcibly pull it off the teeth, making quite a noise as it did so. A new small ring solved the problem.

Booger1

Chainring is worn some......even on all new parts there is a break-in period.....while everything gets happy with each other.

FBinNY 

While nothing can fix the problem of imperfect mating new chain/old sprocket, or the opposite, you choice of chain oil can make a big difference. A good chain oil will act to dampen all the tiny impacts that cause the noise and make a drivetrain quieter.

If you don't want to replace stuff, and the noise annoys you, changing your chain oil could be a cheap fix.

hyhuu

It's definitely quieter after I applied a coat of lube, but that seems to last only a couple hundred miles.

I have a related question: Does a worn chainring shorten the life of the chain or cassette?

Thanks.

FBinNY 

There's some debate about the effect of worn sprockets on chains. I'm of the opinion that Chains wear sprockets, but sprockets don't wear chains. That's because the chain wear happens inside the chain as it winds onto and off a sprocket, and that's the same regardless of the condition of the sprocket. But there are qualified opinions to the contrary.

One difference may be that in machinery the speeds are higher, so the effects of the impacts of the teeth are significant, where they aren't at bike speeds.

fietsbob

If you replace a new chain on a worn sprocket , it will wear quicker to fit the worn teeth,
, but as FB says , chains wear first. so it is better to prematurely replace the chain .
to extend the wear life of the chainwheels it pulls on..

FBinNY 

This is exactly opposite to what I said. "Chains wear sprockets, but sprockets don't wear chains".

While an old chain will rapidly age a sprocket, I don't believe the opposite is true. If you think about standard practice in the bike world, replacing multiple chains over the life of a single cassette, you'll see that it's consistent with my theory.

In 45+ years I have yet to hear a single explanation of how an older sprocket would increase the rate of chain wear. (for bicycles)

rogerstg

Unless you're using some special oil like FB's Chain L, you should probably be lubing at least every couple hundred miles anyway.

FBinNY 

Even with Chain-L the noise will come back as the lube fades out. It will take longer than with some other lubes, but Chain-L isn't a miracle product and can't magically make old stuff new.

All I can honestly say, is that Chain-L will make your chain run quieter and that it'll stay quieter longer than the other products out there. However Chain noise is a very subjective issue. What one person will consider irritatingly noisy, someone else will consider normal.

fietsbob

New chain, and I Flipped over the R'off cog to use it longer (they're symmetrical).. , it felt odd, for a while,
now It's better, I doubt I un wore the hub cog..

ThermionicScott 

Pics?

As long as you aren't letting your chains get too "stretched" before replacing them, I think this is just a minor annoyance. Some folks run their chainrings until the teeth are about to snap off with no other troubles.

Booger1

Everything you wanted to know about chains but were afraid too ask:
https://chain-guide.com/basics/7-1-6-...eshooting.html

Burton

Since you bought the bike used, the chain and cassette are brand new and the issue only happens on the smaller chainring of the double - I'd bet that's where the previous owner spent most of his time and its likely this isn't the first chain / cassette to be replaced on the bike.

If the teeth are worn, lubing the chain might mask the problem, but changing the ring is a better solution. A second opinion at a shop to confirm wear would be a good idea.

FBinNY 

An easy (free) way to measure chainring wear is to use a screwdrive blade to lift the chain away from the ring at the halfway wrapped position. A new chain on a new ring will barely lift away. With wear the distance you can lift it increases. If you can lift the chain away until you see over 1/4" of daylight between the chain and ring, one or both are badly worn. If the chain is new, you know it's the ring.

IMO, there's no harm in riding with worn rings until you cannot because of skip, or suck. So it's a question of how much the noise bothers you, and whether it's worh paying for a new ring to get rid of it, which is strictly a personal judgement.

My road bike's rings are so worn that they make Ninja stars look like frisbees, but they still run OK. They're a bit noisy under heavy power, but I don't hear any chain noise otherwise.