Bicycle Mechanics - noisy chain

Hi

I'm running a track chain on fixed gear bike but can't stop the chain making
a slight grating type noise. It's not old - only about 700 miles - but
has never run quietly. I've cleaned and lubed it thoroughly but it still
makes the noise. Any ideas anyone?

Cheers!

I'm not totally sure about threading the chain on a fixed gear bike, but a grating noise probably means the chain is rubbing against something on each revolution. That occurs on my more conventional bike when either the front or rear derailleur is not adjusted properly, causing the chain to grind against it as it goes around. Could your problem be something similar?

Is the chainline spot on, and is the sprocket worn?

Is the chainline spot on, and is the sprocket worn?

..the chain line's perfect and the cog's as new as the chain. 'Grating' is probably a little misleading but I can't think of a better way to describe it. Nothing's touching anything that it shouldn't be, and the noise is definately inherent in the chain.

..thanks for trying to help guys :)

..the chain line's perfect and the cog's as new as the chain. 'Grating' is probably a little misleading but I can't think of a better way to describe it. Hmm, maybe an audio version of "post a pic" is in order. D'you have a microphone you can plug into your sound card (they often come with the computer)? Can you get the bike close to it? Record a few seconds of the sound as a wav or mp3, and post it here.

Do you feel anything in telegraphing thru the pedals that corresponds to the sound?

Any ideas anyone?

Sure you got the right size chain for your sprocket size (width)?

what kind of lubrication do you use? ive found that on a fixed gear the wax based stuff wears off very quickly and results in that annoying "lube me" noise. now i use oil, i feel that it lasts longer than a wax based lube.

maybe its not the chain. try taking the chain off and spinning the crank. does it still make the noise? then it could be the bottom bracket. try the rear hub also...since its a fixe, it might even be the front...

It is probably just the "tight" spot in the revolution of the cranks. Most chainrings are not perfectly round which is not a problem in a der based drivetrain because the der makes up for the changes in chain tension. On a fixie it has no where to go so it gets really tight in a certain spot when pedaled, the chain often vibrates up and down rapidly during the tight spots and then droops a little on the looser spots. You could move the rear wheel slightly forward and help it some but it might result in the chain being too loose. Another option is to try to center the chainring on the crank. It can be done by loosening the chainring bolts and then pedaling to where the tight spot is and tapping the chain with a crescent wrench. Sheldon Brown explains this better on his site.

Cheers,
-Ryan

You might also want to check the hub, it could be a little tight or dry.
Altho, Biker Ryan has a good bet, particularly if the sound pulses.

..I've done all the recomended tests and have limited the problem down to the contact between cog and chain. The noise is created by the chain links as it passes round the cog - it doesn't have a 'damaged' sound, just seems a little more noticable than I'm used to. I've changed to a wax based lube and this seems to have made a difference. Perhaps there's just some gunk in the rollers. I'll try soaking it in de-greaser and see what happens.

Thanks again everyone :)