Aluminium dropout twisted slightly .

Discussion in 'Cycling Equipment' started by Chris James, Jun 15, 2003.

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  1. Chris James

    Chris James Guest

    I have an all aluminium frame . There is a very slight twist in the dropout where the rear mech
    hanger attaches . What happened : the chain tangled on the rear mech and pulled the whole mech into
    the rear wheel . Ugly . Busted loads of spokes . The rear mech is a write-off and I'll have to bash
    out the very bent hanger ( or replace it ) . Problem is enough force was conducted into the frame
    dropout area to pull it in , with a slight twist .

    The temptation is to grab hold of it with an enormous pair of pliers and pull it straight again . I
    suspect this may not be the right answer though .

    Do I need to see an expert who may use heat ?

    All suggestions welcomed .

    Thankyou . Chris James
     
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  2. Phil Holman

    Phil Holman Guest

    "Chris James" <[email protected]> wrote in message
    news:[email protected]...
    > I have an all aluminium frame . There is a very slight twist in the dropout where the rear mech
    > hanger attaches . What happened : the chain tangled on the rear mech and pulled the
    whole mech
    > into the rear wheel . Ugly . Busted loads of spokes . The rear mech is a write-off and I'll have
    > to bash out the very bent
    hanger
    > ( or replace it ) . Problem is enough force was conducted into the frame dropout area to
    pull it
    > in , with a slight twist .
    >
    > The temptation is to grab hold of it with an enormous pair of pliers
    and
    > pull it straight again . I suspect this may not be the right answer though .
    >
    > Do I need to see an expert who may use heat ?
    >
    > All suggestions welcomed .

    The aluminum frame can be cold set to return it to it's proper geometry. The risk is that a crack
    has been initiated and this will result in a future failure. A non destructive test inspection can
    be carried out to check for a crack but this is an expensive operation and hardly cost effective for
    the price of a frame. I have straightened out a RD hanger on an aluminum bike but here the load is
    not large and the likely consequence of failure not catastrophic. It is generally accepted that for
    an aluminum frame, the risk is not worth the price of a new frame.

    Phil Holman
     
  3. Otto

    Otto Guest

    On Sun, 15 Jun 2003 13:25:23 +0100, [email protected] wrote:
    >
    > The temptation is to grab hold of it with an enormous pair of pliers and pull it straight again .
    > I suspect this may not be the right answer though .
    >

    I tried to do that on my Cannondale frame and broke off the bottom half of the derailleur hanger,
    ruining the frame.
     
  4. A Muzi

    A Muzi Guest

    "Chris James" <[email protected]> wrote in message
    news:[email protected]...
    > I have an all aluminium frame . There is a very slight twist in the dropout where the rear mech
    > hanger attaches . What happened : the chain tangled on the rear mech and pulled the whole
    mech
    > into the rear wheel . Ugly . Busted loads of spokes . The rear mech is a write-off and I'll have
    > to bash out the very bent
    hanger
    > ( or replace it ) . Problem is enough force was conducted into the frame dropout area to pull
    it
    > in , with a slight twist .
    >
    > The temptation is to grab hold of it with an enormous pair of pliers and pull it straight again .
    > I suspect this may not be the right answer though .
    >
    > Do I need to see an expert who may use heat ?

    Yes you could try to straighten it. No, don't heat it. You might want to secure a replacement just
    in case it cracks in bending.

    --
    Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971
     
  5. In article <[email protected]>, [email protected] says...
    >
    >
    >I have an all aluminium frame . There is a very slight twist in the dropout where the rear mech
    >hanger attaches . What happened : the chain tangled on the rear mech and pulled the whole mech into
    >the rear wheel . Ugly . Busted loads of spokes . The rear mech is a write-off and I'll have to bash
    >out the very bent hanger ( or replace it ) . Problem is enough force was conducted into the frame
    >dropout area to pull it in , with a slight twist .
    >
    >The temptation is to grab hold of it with an enormous pair of pliers and pull it straight again . I
    >suspect this may not be the right answer though .
    >
    >Do I need to see an expert who may use heat ?
    >
    >All suggestions welcomed .

    I would take the large wrench approach and be carefull not to go too far. If the dropout is going to
    break, then it will break. Not much you can do about htat.
    -----------------
    Alex __O _-\<,_ (_)/ (_)
     
  6. bball

    bball Guest

    On Mon, 16 Jun 2003 12:09:37 -0400, Alex Rodriguez <[email protected]> wrote:

    >In article <[email protected]>, [email protected] says...
    >>
    >>
    >>I have an all aluminium frame . There is a very slight twist in the dropout where the rear mech
    >>hanger attaches . What happened : the chain tangled on the rear mech and pulled the whole mech
    >>into the rear wheel . Ugly . Busted loads of spokes . The rear mech is a write-off and I'll have
    >>to bash out the very bent hanger ( or replace it ) . Problem is enough force was conducted into
    >>the frame dropout area to pull it in , with a slight twist .
    >>
    >>The temptation is to grab hold of it with an enormous pair of pliers and pull it straight again .
    >>I suspect this may not be the right answer though .
    >>
    >>Do I need to see an expert who may use heat ?
    >>
    >>All suggestions welcomed .
    >
    >I would take the large wrench approach and be carefull not to go too far. If the dropout is going
    >to break, then it will break. Not much you can do about htat.
    >-----------------
    >Alex __O _-\<,_ (_)/ (_)
    >
    I had a similar twisted dropout problem with a STEEL frame. I clamped the dropout in a vise and
    rotated the bike counterclockwise slightly. Two trials and I got it nice. This method gives you a
    nice grip on the dropout and good control for the counter force. Good luck with aluminum.

    Bruce Ball
     
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