Specialized Tarmac BB Knocking Noise?

[Deleted User]
[Deleted User] Posts: 0
edited August 2011 in Road beginners
Just brought a specialized Tarmac Used everthing is fine except a knocking noise from the crank/BB when putting the power down.

I can feel it through my pedal, on the non crank side at the top of the revolution.

Any ideas? :?

Comments

  • keef66
    keef66 Posts: 13,123
    drop the chain off the inner ring and see if you can feel any play or roughness when spinning the cranks. Can you feel any side to side play when you push / pull on them?
  • [Deleted User]
    [Deleted User] Posts: 0
    No play or ruffness when spining the cranks, no side to side play either.
  • keef66
    keef66 Posts: 13,123
    Doesn't sound like the BB then. What chainset is it? If it's one of the Shimano HT2 you could try removing and reinstalling the non drive side crank
  • [Deleted User]
    [Deleted User] Posts: 0
    Its shimano 105 5700, not sure on the specific model.
  • Chris65
    Chris65 Posts: 41
    Is it a BB30 bottem bracket?
    I had a similar problem. If the noise comes on at the same pedal position each revelution it is probabaly slight movement of the bottom bracket. My LBS solved this by applying a thin film of locktight.
    Are the stem bolts torqued up correctly and is there some grease on them. It may be they are "dry".
    Listening for noises can spoil your ride

    I posted the above to another question about knocking sound
  • [Deleted User]
    [Deleted User] Posts: 0
    No its not BB30.

    Found some info on what might be causing it :

    Bottom Bracket Cups/Retaining Rings Loose?

    Because of the threading of normal bottom brackets, the cups are self-tightening to a point. This sometimes leads to careless installation, particularly on the right (fixed cup) side. If the right cup is slightly loose, it won't necessarily unscrew itself, but it won't really tighten itself up fully either. The symptom of this is an occasional creak or clunk usually as the left crank goes "over the top" when pedaling hard.

    This is a surprisingly common, and frequently missed, casue of unwanted noises. Generally you should check the items above first, because they're easier to deal with. You can't reliably check the tightness of the bottom bracket mounting without removing the cranks, but sometimes you can diagnose it this way:

    Not sure but it sounds like whats happening.

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