I have a noisy drive train on my Trek road bike with Shimano 105. It's very noticeable on the big cog, and is not as bad on the small cog, but still irritating. It's just a constant whiring noise. I am going to give it a clean all around, but it is really not too dirty at all at the moment, and i don't think that will be the solution. Any ideas where else to look?

  • just to add - it's over all the gears, not just the extreme opposit ones, where i know there will be a bit of rattle
    – Tom
    Aug 19, 2015 at 15:25
  • Have you checked to see if the chain is rubbing somewhere?
    – Batman
    Aug 19, 2015 at 15:28
  • Did you check chain wear?
    – Michael
    Aug 19, 2015 at 16:28

1 Answer 1


I would recommend, as you stated you were already doing, that you give your driving mech a full cleaning. Run some hot water and a degreaser through all of your gears and your chain, (thoroughly). After that, (it helps if you have a repair stand for this), take some nice chain oil and run it on your chain real good, then shift through all of your gears and run that lube thoroughly through your gears. Personally, I do this two or three times to make sure everything is well lubed. Don't use too much, but dont be stingy with it either. Also, be sure you lube both sides of the chain.

I'm sure the mech itself is ok, but maybe it would be good to check and make sure your front and rear dérailleur are clean so that your shifting is smooth. Also check to make sure your gears are indexed correctly.

Hopefully something here helps you out. Good luck!

  • Also check for wear – especially on the chain, but also on the cogs and chainrings. Then check adjustments, especially indexing (as mentioned) if you are off just slightly the chain may be constantly trying to shift.
    – dlu
    Aug 19, 2015 at 19:47
  • With 'both sides of the chain' do you mean left and right or inside (as in the part which runs on the cogs) and outside?
    – stijn
    Aug 19, 2015 at 20:03
  • @stijn I'm sorry, yes you want to lube the part that touches the gears and the opposite side as well, not the outer flat part.
    – Weirix
    Aug 19, 2015 at 20:08
  • my last post was deleted, so sorry for delay, i'm not allowed to say t**nks, that's why they deleted my post. So gave the bike a good clean, slightly improved the noise, but not completely gone. Could be wear to the chain thought it's looks fine must have done around 1500 - 2000 km. It's very strange that the noise is much louder while i'm on the big cog. Seems to reduce a bit when i'm stanfing on my pedals
    – Tom
    Sep 4, 2015 at 12:51
  • Hmm. @Tom have you looked at the bottom bracket? If the noise kind of goes away when you stand on the bracket, it sounds like you might want to check all your front mech and maybe hit it with some kind of lubricant. That would also explain why the noise comes loudest when you're in your big ring. The more you spin, the more noise you get,
    – Weirix
    Sep 4, 2015 at 13:12

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