The rear of my bike is making a grinding noise while pedalling. There's no noise without the downward pressure of being on it and it's only grinding while I pedal. Any suggestions please ?

  • 2
    Only while pedaling sounds as if it is drivetrain-related: worn chain, new chain with worn rear cogs not matching up, missing lubrication, rear derailleur needs adjustment.
    – DoNuT
    Jan 11 at 14:01
  • 1
    Hi, welcome to bicycles. Is there any way you could get someone to take a video while you pedal slowly? Right now we not only don't know where in the drive train the noise is coming from, we don't know if you have a belt-drive IGH bike or a bike with a traditional chain-derailleur setup.
    – DavidW
    Jan 11 at 14:22
  • I forgot in my listing: bent derailleur hanger, freehub. We need a better description of the issue and what's on the bike in terms of components. Does it occur in all gears, is shifting consistent, does the grinding correlate to the pedaling cadence, anything that helps to narrow it down....
    – DoNuT
    Jan 12 at 6:51

2 Answers 2


sounds like your Bottom Bracket Bearings are worn out and need replacing. I'm going to guess that you have a MTB. It common for bottom bracket bearings to make grinding noises when worn. This is do to the harsh environment of dirt mud water your bike is exposed to.

  • That's a long shot without any video material or more detailed description of the issue. I admit that bearings can make annoying noises when they're gone and it is hard to locate them riding the bike.
    – DoNuT
    Jan 12 at 6:47
  • 1
    If you ride a mountain bike in muddy conditions, you get grinding sounds from your chain well before your bottom bracket
    – Paul H
    Jan 12 at 7:17
  • @PaulH and your jockey wheels, and anything anywhere near the tyres, going by yesterday's ride. Hub bearings can also make a grinding noise if failing
    – Chris H
    Jan 14 at 17:22

Without more information, no one can confidently diagnose the cause of your problem.

Your symptoms happened to me when I bent an axle. The rear bearings started grinding on each other. I got out of it with the same hub, cups and cones, but the bearings and axle needed replacing.

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