nasty noise from crank - What is it?

Discussion in 'UK and Europe' started by danielstevens, Aug 19, 2004.

  1. danielstevens

    danielstevens New Member

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    Hello

    Zero knowledge of bike maintenance i'm afriad. Basically my bike has started to make a funny noise, its coming from the crank (the bit the peddles are attached to) or the round bit in the middle that is attached to the crank.

    It's making a brittle sound and feels very brittle, especailly when i put alot of pressure on the peddles, going up hill for example. I have been to the bike shop and the guy just tightened up the bit where the crank is attached. A bit of oil has helped but the problem remains. I'm sure something pretty serious is up although i continue to ride for a hour a day to and from work. Its one of those annoying problems that is difficult to diagnose unless you ride the bike yourself.

    If anyone has got any ideas as to what the problem might be i would appreciate it

    many thanks

    Dan
     
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  2. Simon Mason

    Simon Mason Guest

    "danielstevens" <[email protected]> wrote
    in message news:[email protected]
    >
    > Hello
    >
    > Zero knowledge of bike maintenance i'm afriad. Basically my bike has
    > started to make a funny noise, its coming from the crank (the bit the
    > peddles are attached to) or the round bit in the middle that is
    > attached to the crank.
    >
    > It's making a brittle sound and feels very brittle, especailly when i
    > put alot of pressure on the peddles, going up hill for example. I have
    > been to the bike shop and the guy just tightened up the bit where the
    > crank is attached. A bit of oil has helped but the problem remains. I'm
    > sure something pretty serious is up although i continue to ride for a
    > hour a day to and from work. Its one of those annoying problems that is
    > difficult to diagnose unless you ride the bike yourself.


    Could be about to crack like mine did see:

    http://www.simonmason.karoo.net/zcrank.htm

    Mine was caused by someone who had the bike before me not tightening the nut
    to the correct torque setting.
     
  3. JohnB

    JohnB Guest

    danielstevens wrote:
    >

    I've been caught out.

    I thought this was another PS thread.

    John B
     
  4. I thought that was another post about Psmith from the title...
     
  5. Pete Biggs

    Pete Biggs Guest

    danielstevens wrote:
    > It's making a brittle sound and feels very brittle, especailly when i
    > put alot of pressure on the peddles, going up hill for example.


    When it does make a noise, is it one sound per crank revolution? A click
    or clunk? Could be a loose crank if it's on one side only; crank will
    need replacing if it comes loose again after retightening. Could be
    elsewhere on the bike but coinciding with pedalling, including from the
    rear wheel hub.

    Or could be a loose or faulty bottom bracket (part inside frame between
    cranks), especially if cranks have play when grabbed and pulled sideways.

    Or is it more random tinkly noise? : Bottom bracket problem, perhaps. Or
    again, it could actually be coming from somewhere else.

    Does it happen when standing up on the pedals (not sitting on saddle)?

    > I have
    > been to the bike shop and the guy just tightened up the bit where the
    > crank is attached. A bit of oil has helped but the problem remains.
    > I'm sure something pretty serious is up although i continue to ride
    > for a hour a day to and from work. Its one of those annoying problems
    > that is difficult to diagnose unless you ride the bike yourself.


    Yes and particularly difficult to diagnose over the internet without
    seeing or hearing it. You and/or the bike shop need to keep eliminating
    things to track it down. Good luck.

    ~PB
     
  6. Roos Eisma

    Roos Eisma Guest

    "Pete Biggs" <pblackcherry{remove_fruit}@biggs.tc> writes:

    >danielstevens wrote:
    >> It's making a brittle sound and feels very brittle, especailly when i
    >> put alot of pressure on the peddles, going up hill for example.


    >When it does make a noise, is it one sound per crank revolution? A click
    >or clunk? Could be a loose crank if it's on one side only; crank will
    >need replacing if it comes loose again after retightening. Could be
    >elsewhere on the bike but coinciding with pedalling, including from the
    >rear wheel hub.


    >Or could be a loose or faulty bottom bracket (part inside frame between
    >cranks), especially if cranks have play when grabbed and pulled sideways.


    >Or is it more random tinkly noise? : Bottom bracket problem, perhaps. Or
    >again, it could actually be coming from somewhere else.


    >Does it happen when standing up on the pedals (not sitting on saddle)?


    And if you feel it mainly on one side: ball bearings inside the pedal.

    Roos
     
  7. danielstevens

    danielstevens New Member

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    thanks for comments on this - i think its one sound per crank revolution, its more of a clicking sound(s) then a clunk. The crank has already been tightened so i think we can rule that out. I think the bottom braket - (thanks i now know what this bit is called!) - may be at faulty. I suppose it may be a question of opening the thing up and having a look inside. Happens when both standing and sitting.

    cheers

    Dan.



     
  8. Pete Biggs

    Pete Biggs Guest

    danielstevens wrote:
    > thanks for comments on this - i think its one sound per crank
    > revolution, its more of a clicking sound(s) then a clunk. The crank
    > has already been tightened so i think we can rule that out.


    Not necessarily. A crank that's damaged badly enough may soon click or
    clunk again after it's refitted. The square hole (assuming the most
    common type) of the aluminium crank can deform or become too large for the
    steel bottom bracket spindle it wedges onto.

    Some more simple things to check: Chainring bolts are tight, crank is not
    tapping front derailleur, shoe laces aren't tapping crank (I'm not
    joking), pedals are ok (try different pedals if you have/can borrow any).

    > I think
    > the bottom braket - (thanks i now know what this bit is called!) -
    > may be at faulty.


    Could be.

    > I suppose it may be a question of opening the thing
    > up and having a look inside.


    A lot of them are sealed units and can't be serviced.

    > Happens when both standing and sitting.


    Not the saddle or seatpost then, and won't be a problem with hub or chain
    if it's one click per crank rev. We're making progress :)

    ~PB
     
  9. Pete Biggs

    Pete Biggs Guest

    [BB]
    >> I suppose it may be a question of opening the thing
    >> up and having a look inside.

    >
    > A lot of them are sealed units and can't be serviced.


    Just in case that worries you: they can easily and cheaply be replaced.

    ~PB
     
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