Aluminium dropout twisted slightly .

[Chris James]

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

 

[Phil Holman]

"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

 

[Otto]

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.

 

[A Muzi]

"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

 

[Alex Rodriguez]

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 _-\<,_ (_)/ (_)

 

[bball]

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