Right Crank, making stress cracking noise.

Discussion in 'The Bike Cafe' started by complience, Jul 31, 2005.

  1. complience

    complience New Member

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    My KHS 300 flite 2004.

    Came with the Sora Groupset.

    Last month i started using clippless pedals on it.

    But now when i strike hard down with my right leg at full power. There is a small sharp cracking sound, and i think i can feel vibration through the shoe.

    Its Very annoying, I think the source must a stress facture within the Crank itsself.. or the Front chain rings flexing under the pressure.

    Ive only been riding it for 4 months or so and done 4000k on it. Im not that heavy 10stone, also I do like to stand alot while pedaling.

    Ive tried Tighting every screw and bolt.. taken off the cranks and made sure they are firmly back in place on the bracket, and tried my old clipin pedals, nothing gets rid of the "crack" every time i pedal hard (which is just about 100% of the time)

    Are cracks forming within cranks very common on budget equipment like sora?

    I dont want to spend £30 on a new crank with chain rings.. if its not going to fix the problem.
     
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  2. imslayer

    imslayer New Member

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    that sucks i dont know what to say
     
  3. complience

    complience New Member

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  4. oldbobcat

    oldbobcat Well-Known Member

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    Everybody I know who has ever cracked a crank has said that failure was sudden. If there were warning signs, they were visible, not audible.

    If you have an adjustable cups-and-cones bottom bracket, it sounds like your BB shell needs facing. Pro-quality shops that have the facing tools can do this. (Headsets should be similarly faced.)

    If the facings are not perfectly square, then the the seating of the bearing cups distorts when the lockring is tightened down. The balls are now running under uneven tension in the bearing, a condition undetectable by just spinning the spindle unloaded. Under the torque, however, the balls will click as they squeeze past the tight side of the bearing.
     
  5. oldbobcat

    oldbobcat Well-Known Member

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    On the other hand, if you want to buy a new bike, that's OK, too.
     
  6. complience

    complience New Member

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  7. oldbobcat

    oldbobcat Well-Known Member

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    I haven't bought a BB in 25 years, so I wouldn't know. I'm in the States, so I'd guess that getting out from under for less than $40 is a pretty good deal. There isn't a lot of price cutting on BBs. If everything fits and the BB shell checks out, I'd say go for it.
     
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