When cycling my bottom bracket sometimes starts to make a clunking noise, I can get rid of the noise normally by doing one or two strong pedal strokes. Is this anything serious does the bracket need to be looked at?

  • 2
    First, make sure that the problem is not a loose crank arm, as this can quickly destroy the arm and the crank axle. (Ie, this would be an "emergency".) Next, consider that the BB cartridge (if it is a cartridge setup) may be loose -- tightening the cups holding it may cure your problem. Commented Jul 31, 2016 at 18:27
  • I agree with what Daniel said. But I'd say to check the pedals too as I've had noisy pedals before and suspected the bottom bracket initially before finding out otherwise.
    – jonifen
    Commented Jul 31, 2016 at 21:36
  • If it is a loose crank arm and it was a square taper kind then it would be ruined by now and it will be wobbling and maybe even loosening the crank bold by itself.
    – Tooniis
    Commented Jan 14, 2020 at 2:46
  • Freewheels can also cause clunking noises. If your bike has a freewheel then get the rear wheel off and try to move the freewheel up and down (don't spin it, but rather rock it vertically) and check for any movement. If it moves then its bearings are worn out and you most probably need to replace it. Such a freewheel might fail completely and start to spin in both directions freely if you continue to ride with it. That wouldn't cause damage to other parts, but if you ride for a long distance then it might leave you stranded away from home.
    – Tooniis
    Commented Jan 14, 2020 at 2:50

1 Answer 1


First, it may not be your bottom bracket. Creaks and clunks are notoriously difficult to localize. If you can reproduce it with the bike on a stand (or upside down on the ground), it may be easier to know for sure.

If it is your bottom bracket, you should replace it (or less commonly, replace only its bearings, depending on the type of bottom bracket).

If you continue to ride, eventually it will probably get worse, but this won't harm anything other than the bottom bracket, so it's not particularly urgent.

  • Okay thanks! I will probably replace it then, I have a 1980's raleigh royal that I bought 2nd hand and I am just starting to realise that regardless of what the guy who sold it to me said all the 'original parts' are so rusted that I need to replace them all and so it's just another thing to the list!
    – Goods
    Commented Jul 31, 2016 at 16:38
  • @goods You'll have to look into the archives on how to adjust and change a very old BB like that. It would be good to take it apart, degrease it and repack it with new grease in the very least. There is also a real possibility that you could simply have a loose BB cupset and it needs tightening.
    – user26705
    Commented Aug 1, 2016 at 3:34
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    @BTeam: Another alternative would be to just replace the BB with a modern cartridge type BB - not as "authentic", but less work and probably more durable. This of course assumes there are compatible cartridge BBs...
    – sleske
    Commented Aug 1, 2016 at 8:11
  • @sleske: That is true. They are less maintenance. I was thinking of the cheapest route though. Ball bearings are pennies a piece. Good thinking though.
    – user26705
    Commented Aug 1, 2016 at 17:45

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