Bent derailleur hanger repair?

[Lou Holtman]

Tom Nakashima wrote:
> "Lou Holtman" <[email protected]> wrote in message
> news:[email protected]...
>> Tom Nakashima wrote:
>>> "Lou Holtman" <[email protected]> wrote in message
>>> news:[email protected]...
>>>> Tom Nakashima wrote:
>>>>> "A Muzi" <[email protected]> wrote in message
>>>>> news:[email protected]...
>>>>>> Mike Jacoubowsky wrote:
>>>>>>> Bent-up derailleur hangers are rarely a result of a poor set-up on
>>>>>>> the bike. It could happen, but more likely it's something that got
>>>>>>> caught in the chain or derailleur (it doesn't take much; a small twig
>>>>>>> can do it, one customer picked up a piece of cloth). The other thing
>>>>>>> to look for, that would go back to the assembly of the bike (most
>>>>>>> likely at the factory) would be a bad chain pin, causing the chain to
>>>>>>> separate and come apart while going through the derailleur, which can
>>>>>>> lead to very bad things. This will almost always be at the connecting
>>>>>>> point in the chain. Definitely something to look for.
>>>>>> That's all true, but don't you find the bulk of them show pavement
>>>>>> marks on the derailleur body? Once bent inward, catching a spoke is
>>>>>> almost inevitable.
>>>>>> --
>>>>>> Andrew Muzi
>>>>>> www.yellowjersey.org
>>>>>> Open every day since 1 April, 1971
>>>>> Sorry, but you guys lost me here, how can a small twig caught in the
>>>>> chain bend a derailleur hanger? Seems to me you have to knock them
>>>>> pretty hard against concrete or a rock to bend them or break them.
>>>>> -tom
>>>> Never had chainsuck then. Broke my derailleur hanger off two weeks ago.
>>>> Fotunately it was a replacable one. Same happens when a twig gets
>>>> caught.
>>>>
>>>>
>>>> Lou
>>>> --
>>>> Posted by news://news.nb.nu (http://www.nb.nu)
>>> Yes I have had chainsuck many times,
>>> but never broken a derailleur hanger.
>>> -tom
>>
>> You can't imagine that when this happes and you are in one of the larger
>> sprockets that when the derailleur slaps against the chainstays the
>> derailleur cage can easily end up in the spokes?
>>
>> Lou
>> --
>> Posted by news://news.nb.nu (http://www.nb.nu)
>
> Lou,
> you can throw and chain off the either big or small chainring and get
> chainsuck. I've have thrown chains and had it get stuck between the
> hub and frame, but not enough to break off the derailleur hanger.
> And I've also had branches, twigs get into the chain, but again never
> a broken derailleur hanger.
> But if you say you have I believe you.
> -tom
>
>


Tom, by chainsuck I mean that the chain doesn't 'break loose' at the
lower part of the chainring. It isn't thrown of the chain ring it just
keep following it. All the slack is eaten up and the derailleur cage
slaps against the chainstays and is easily diverted into the spokes and
when that happens hell breaks loose.


Lou
--
Posted by news://news.nb.nu (http://www.nb.nu)

 

[Tom Nakashima]

"Lou Holtman" <[email protected]> wrote in message
news:[email protected]...
> Tom Nakashima wrote:
>> "Lou Holtman" <[email protected]> wrote in message
>> news:[email protected]...
>>> Tom Nakashima wrote:
>>>> "Lou Holtman" <[email protected]> wrote in message
>>>> news:[email protected]...
>>>>> Tom Nakashima wrote:
>>>>>> "A Muzi" <[email protected]> wrote in message
>>>>>> news:[email protected]...
>>>>>>> Mike Jacoubowsky wrote:
>>>>>>>> Bent-up derailleur hangers are rarely a result of a poor set-up on
>>>>>>>> the bike. It could happen, but more likely it's something that got
>>>>>>>> caught in the chain or derailleur (it doesn't take much; a small
>>>>>>>> twig can do it, one customer picked up a piece of cloth). The other
>>>>>>>> thing to look for, that would go back to the assembly of the bike
>>>>>>>> (most likely at the factory) would be a bad chain pin, causing the
>>>>>>>> chain to separate and come apart while going through the
>>>>>>>> derailleur, which can lead to very bad things. This will almost
>>>>>>>> always be at the connecting point in the chain. Definitely
>>>>>>>> something to look for.
>>>>>>> That's all true, but don't you find the bulk of them show pavement
>>>>>>> marks on the derailleur body? Once bent inward, catching a spoke is
>>>>>>> almost inevitable.
>>>>>>> --
>>>>>>> Andrew Muzi
>>>>>>> www.yellowjersey.org
>>>>>>> Open every day since 1 April, 1971
>>>>>> Sorry, but you guys lost me here, how can a small twig caught in the
>>>>>> chain bend a derailleur hanger? Seems to me you have to knock them
>>>>>> pretty hard against concrete or a rock to bend them or break them.
>>>>>> -tom
>>>>> Never had chainsuck then. Broke my derailleur hanger off two weeks
>>>>> ago. Fotunately it was a replacable one. Same happens when a twig gets
>>>>> caught.
>>>>>
>>>>>
>>>>> Lou
>>>>> --
>>>>> Posted by news://news.nb.nu (http://www.nb.nu)
>>>> Yes I have had chainsuck many times,
>>>> but never broken a derailleur hanger.
>>>> -tom
>>>
>>> You can't imagine that when this happes and you are in one of the larger
>>> sprockets that when the derailleur slaps against the chainstays the
>>> derailleur cage can easily end up in the spokes?
>>>
>>> Lou
>>> --
>>> Posted by news://news.nb.nu (http://www.nb.nu)
>>
>> Lou,
>> you can throw and chain off the either big or small chainring and get
>> chainsuck. I've have thrown chains and had it get stuck between the
>> hub and frame, but not enough to break off the derailleur hanger.
>> And I've also had branches, twigs get into the chain, but again never
>> a broken derailleur hanger.
>> But if you say you have I believe you.
>> -tom
> Tom, by chainsuck I mean that the chain doesn't 'break loose' at the
> lower part of the chainring. It isn't thrown of the chain ring it just
> keep following it. All the slack is eaten up and the derailleur cage slaps
> against the chainstays and is easily diverted into the spokes and when
> that happens hell breaks loose.
> Lou
> --
> Posted by news://news.nb.nu (http://www.nb.nu)

I can somewhat visualize what you're saying about the chain slack.
As I said, and not sure if this contributes to less chain slack, but I use a
med to short cage derailleur, downtube index shifters which my shifts are
smooth and never quick. My cadence has always been smooth.
I've seen riders with lots of chain slapping, seems like lots of excessive
chain, partly thinking it's due to being in the wrong gear (pedaling faster
than needed on the flats or descents) and not having a smooth cadence.
-tom

 

[datakoll]

the deray adjustments are not adjusted for the "throwing" shifting
that is asking chain to go from one set gears to a set the system
either wasn't designed for or wasn't adjusted for or both.
does seem a stick stuck up thru the 2 chain run would lever the chain
and then deray over into a wheel. but who runs over sticks?
Hi-End (or low end in NE) 1980's tiwanese/japanese steels used for
hangers, cages and derays are bendable and rebendable back into
service after total pretzel wipeouts. expletive deleted.
spioke guards used here are made from low quality plastics, not
durable.

 

[philcycles]

datakoll wrote:
> get the wheel off, replace a 1/2 or larger threaded rod with nuts/
> washers in the droputs, then find an aluminum fabricator if aluminum
> or a welder who brazes.
> The experienced welder will heat the metal to a very stiff putty
> and bend it back straight no problem.
> if the deray is "ruined" then fix it with a hammer, pry bar...
> remember, hold both unbent sides fixed, rebend only the bends

HEATING IS TOTALLY UNNECESSARY AND HARMFUL TO THE PAINT. It';s a steel
frame so it will just bend back cold. Do it with the wheel in and you
won't bend the dropout slot.
Phil Brown

 

[Mike Jacoubowsky]

> Mike Jacoubowsky wrote:
>> Bent-up derailleur hangers are rarely a result of a poor set-up on the
>> bike. It could happen, but more likely it's something that got caught in
>> the chain or derailleur (it doesn't take much; a small twig can do it,
>> one customer picked up a piece of cloth). The other thing to look for,
>> that would go back to the assembly of the bike (most likely at the
>> factory) would be a bad chain pin, causing the chain to separate and come
>> apart while going through the derailleur, which can lead to very bad
>> things. This will almost always be at the connecting point in the chain.
>> Definitely something to look for.
>
> That's all true, but don't you find the bulk of them show pavement marks
> on the derailleur body? Once bent inward, catching a spoke is almost
> inevitable.
> --
> Andrew Muzi

Andy: Absolutely, the majority of derailleurs-into-spokes are caused by
having bent the derailleur inward from a prior incident. But, if we lead
with that theory, the customer will invariably claim that no, those marks
were from *this* incident. Basically, it's always best to come up first with
a theory that doesn't involve the customer having done something wrong, and
then go from there.

Perhaps people are different in Madison?

--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA


"A Muzi" <[email protected]> wrote in message
news:[email protected]...
>>> Dave Smith <[email protected]> wrote:
>>>> My wife's bike suffered a nasty derailleur into the spokes event.
>>>> Fortunately no damage to her, but the derailleur is junk, the wheel
>>>> needs re-spoking and the hanger is bent. There is a pic of the hanger
>>>> at: http://www.westiesd.com/posting/hanger.jpg
>
>> "Joel Mayes" <[email protected]> wrote
>>> I should also add, if the bike is newish take it back to the store.
>>> This sort of thing can not happen with a properly setup bike, your
>>> warranty should cover this job.
>
> Mike Jacoubowsky wrote:
>> Bent-up derailleur hangers are rarely a result of a poor set-up on the
>> bike. It could happen, but more likely it's something that got caught in
>> the chain or derailleur (it doesn't take much; a small twig can do it,
>> one customer picked up a piece of cloth). The other thing to look for,
>> that would go back to the assembly of the bike (most likely at the
>> factory) would be a bad chain pin, causing the chain to separate and come
>> apart while going through the derailleur, which can lead to very bad
>> things. This will almost always be at the connecting point in the chain.
>> Definitely something to look for.
>
> That's all true, but don't you find the bulk of them show pavement marks
> on the derailleur body? Once bent inward, catching a spoke is almost
> inevitable.
> --
> Andrew Muzi
> www.yellowjersey.org
> Open every day since 1 April, 1971

 

[datakoll]

that's a pretty sharp bend there Phil
anyway there's a sense of humor here
if it's heated, the DO will come off.
that's brings us back to AMuzi's slide show
suggesting, like the owner needs to come to grips with this right?
the only measure is -experienced machine/weld/braze LBS
If i bent one that far, attached to frame, that's what I'd go for.
a detachable? 11 pound hammer- anvil
my spare deatchjable '86 is missing!!

 

[Werehatrack]

On Sun, 02 Dec 2007 20:18:59 -0800, Dave Smith <[email protected]> may
have said:

>http://www.westiesd.com/posting/hanger.jpg

Looks like aluminum. If so, while there's nothing to be lost by
trying to straighten it, I would put the chances of success at no
better than one in ten. If it's steel, a little careful reshaping
will most likely restore it to service. If you have not done this
sort of thing before, it might be wise to get someone involved who has
the experience which makes it more likely that success will be
achieved in one go.

If all else fails, there are alternatives to replacing the frame. I'd
recommend that you consult the most versatile of your local bike shops
before proceeding.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

 

[datakoll]

yeah. we should vote on it. I vote with hatrack- it's 20 degrees to
windward of the LBS.

 

[A Muzi]

>>>> Dave Smith <[email protected]> wrote:
>>>>> My wife's bike suffered a nasty derailleur into the spokes event.
>>>>> Fortunately no damage to her, but the derailleur is junk, the wheel
>>>>> needs re-spoking and the hanger is bent. There is a pic of the hanger
>>>>> at: http://www.westiesd.com/posting/hanger.jpg

>>> "Joel Mayes" <[email protected]> wrote
>>>> I should also add, if the bike is newish take it back to the store.
>>>> This sort of thing can not happen with a properly setup bike, your
>>>> warranty should cover this job.

>> Mike Jacoubowsky wrote:
>>> Bent-up derailleur hangers are rarely a result of a poor set-up on the
>>> bike. It could happen, but more likely it's something that got caught in
>>> the chain or derailleur (it doesn't take much; a small twig can do it,
>>> one customer picked up a piece of cloth). The other thing to look for,
>>> that would go back to the assembly of the bike (most likely at the
>>> factory) would be a bad chain pin, causing the chain to separate and come
>>> apart while going through the derailleur, which can lead to very bad
>>> things. This will almost always be at the connecting point in the chain.
>>> Definitely something to look for.

> "A Muzi" <[email protected]> wrote
>> That's all true, but don't you find the bulk of them show pavement marks
>> on the derailleur body? Once bent inward, catching a spoke is almost
>> inevitable.

Mike Jacoubowsky wrote:
> Andy: Absolutely, the majority of derailleurs-into-spokes are caused by
> having bent the derailleur inward from a prior incident. But, if we lead
> with that theory, the customer will invariably claim that no, those marks
> were from *this* incident. Basically, it's always best to come up first with
> a theory that doesn't involve the customer having done something wrong, and
> then go from there.
> Perhaps people are different in Madison?

heh heh
Yep, just as in California, most riders here report merely "JRA" when
suddenly...

I see that years of customer interaction have led you to seek a
non-accusatory approach. That reflects well your 'people skills'. But
it doesn't change the fact that the gear tab was bashed in before the
changer overshifted into the spokes.

As we build and service bikes we shift the rear changer firmly with a
thumb, sans cable, to check the low gear setting as I have advised on
r.b.t. from time to time and admonish pointedly here:
http://www.yellowjersey.org/endweld.html
(purple box near the bottom)
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

 

[Tom Sherman]

Mike Jacoubowsky wrote:
> ...
> Perhaps people are different in Madison?

Indeed. Particularly in the ***** Street neighborhood.

--
Tom Sherman - Holstein-Friesland Bovinia
"Localized intense suction such as tornadoes is created when temperature
differences are high enough between meeting air masses, and can impart
excessive energy onto a cyclist." - Randy Schlitter

 

[Dave Smith]

On Sun, 02 Dec 2007 20:18:59 -0800, Dave Smith <[email protected]>
wrote:

>My wife's bike suffered a nasty derailleur into the spokes event.
>Fortunately no damage to her, but the derailleur is junk, the wheel
>needs re-spoking and the hanger is bent. There is a pic of the hanger
>at: http://www.westiesd.com/posting/hanger.jpg
>
>My question is, is straightening the hanger a repair best left to a
>highly trained bike mechanic, or might I be able to just bend it back
>into shape. I'm fairly good with tools but if there's a chance of my
>making a mess of the job, I'd prefer to leave it to a pro. The bike
>is a Bianchi Veloce triple.
>
>Thanks very much.
>
>Dave

Sorry. I left out a bit of key information.

The bike is steel, a midrange Bianchi with a triple Veloce gruppo.

The wife was on a steep climb and had been on the lowest (largest)
cassette sprocket for a while and had just stood on the pedals when
things went south. She's had a couple of minor crashes on the bike
and that may have damaged the derailleur, though it was working fine
*before* the event.

Thanks very much for all the input. We have a good LBS that I rarely
use as I do most of the work on our bikes. Hmmm. Maybe I should
reconsider that, eh?

 

[A Muzi]

> Mike Jacoubowsky wrote:
>> ...
>> Perhaps people are different in Madison?

Tom Sherman wrote:
> Indeed. Particularly in the ***** Street neighborhood.

Really (shudder) but who would ride _there_?
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

 

[[email protected]]

On Dec 3, 2:42 pm, "Tom Nakashima" <[email protected]> wrote:
>
> Sorry, but you guys lost me here, how can a small twig caught in the chain
> bend a derailleur hanger? Seems to me you have to knock them pretty hard
> against concrete or a rock to bend them or break them.

Stick jumps up into chain while pedaling, gets carried
into the derailleur by the lower chain run, chain jams.
If you stop pedaling before the jam, the stick falls down;
if not, as you pedal the jammed chain, the chain tension
pulls the derailleur up and around the cogs. So it's not
the twig that directly bends the hanger, but your pedaling
force. You can bend or "literally explode" (a la Paul Sherwen)
the derailleur, and bend the hanger.

The time I did this badly, the der was carried around into the
seatstay and actually bent that too. The derailleur wound up
in several pieces with the steel cage twisted up. Fortunately, it
was a steel bike, and Tom Sullivan at Amsterdam Bicycles
of Santa Cruz rebent the rear end including the stay and
dropout back to spec.

Ben

 

[philcycles]

datakoll wrote:
> that's a pretty sharp bend there Phil
> anyway there's a sense of humor here
> if it's heated, the DO will come off.
> that's brings us back to AMuzi's slide show
> suggesting, like the owner needs to come to grips with this right?
> the only measure is -experienced machine/weld/braze LBS
> If i bent one that far, attached to frame, that's what I'd go for.
> a detachable? 11 pound hammer- anvil
> my spare deatchjable '86 is missing!!

Why would the dropout come out? You wouldn't be heating it any where
near the stays. But it will bend back fine if it's steel, which it
looks to be. Oh, and BTW, I'm a frame builder.
Phil brown

 

[datakoll]

On Dec 5, 12:45 pm, philcycles <[email protected]> wrote:
> datakoll wrote:
> > that's a pretty sharp bend there Phil
> > anyway there's a sense of humor here
> > if it's heated, the DO will come off.
> > that's brings us back to AMuzi's slide show
> > suggesting, like the owner needs to come to grips with this right?
> > the only measure is -experienced machine/weld/braze LBS
> > If i bent one that far, attached to frame, that's what I'd go for.
> > a detachable? 11 pound hammer- anvil
> > my spare deatchjable '86 is missing!!
>
> Why would the dropout come out? You wouldn't be heating it any where
> near the stays. But it will bend back fine if it's steel, which it
> looks to be. Oh, and BTW, I'm a frame builder.
> Phil brown

If the dropout's brazed on...
My shade tree experience sez the bend is acute, and the acuteness is
too near the next formation of material...
to ensure a flat, unkinked rebend.
the owner is shade tree...
that's the process herabouts

 

[A Muzi]

>"Tom Nakashima" <[email protected]> wrote:
>> Sorry, but you guys lost me here, how can a small twig caught in the chain
>> bend a derailleur hanger? Seems to me you have to knock them pretty hard
>> against concrete or a rock to bend them or break them.

[email protected] wrote:
> Stick jumps up into chain while pedaling, gets carried
> into the derailleur by the lower chain run, chain jams.
> If you stop pedaling before the jam, the stick falls down;
> if not, as you pedal the jammed chain, the chain tension
> pulls the derailleur up and around the cogs. So it's not
> the twig that directly bends the hanger, but your pedaling
> force. You can bend or "literally explode" (a la Paul Sherwen)
> the derailleur, and bend the hanger.
>
> The time I did this badly, the der was carried around into the
> seatstay and actually bent that too. The derailleur wound up
> in several pieces with the steel cage twisted up. Fortunately, it
> was a steel bike, and Tom Sullivan at Amsterdam Bicycles
> of Santa Cruz rebent the rear end including the stay and
> dropout back to spec.

Notice dent on seatstay above frame end where derailleur expired:
http://www.yellowjersey.org/borga.html
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

 

[A Muzi]

>> datakoll wrote:
>>> that's a pretty sharp bend there Phil
>>> anyway there's a sense of humor here
>>> if it's heated, the DO will come off.
>>> that's brings us back to AMuzi's slide show
>>> suggesting, like the owner needs to come to grips with this right?
>>> the only measure is -experienced machine/weld/braze LBS
>>> If i bent one that far, attached to frame, that's what I'd go for.
>>> a detachable? 11 pound hammer- anvil
>>> my spare deatchjable '86 is missing!!

> philcycles <[email protected]> wrote:
>> Why would the dropout come out? You wouldn't be heating it any where
>> near the stays. But it will bend back fine if it's steel, which it
>> looks to be. Oh, and BTW, I'm a frame builder.

datakoll wrote:
> If the dropout's brazed on...
> My shade tree experience sez the bend is acute, and the acuteness is
> too near the next formation of material...
> to ensure a flat, unkinked rebend.
> the owner is shade tree...
> that's the process herabouts

The forged steel Bianchi Volpe frame ends are indeed brazed in. The bend
is typical and should not present any difficulty to Phil Brown or to me
or to anybody who does this work on a regular basis.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

 

[datakoll]

good point. we know Phil's honest.

 

[richard]

Fix only if it's steel!

A great tool is the old derailleur. Get the longest allen wrench you
can find, put the long in into the bolt that holds the derailleur, and
start bending. That way, at least the dropout hold and threads will
remain true.

Dave Smith wrote:
> My wife's bike suffered a nasty derailleur into the spokes event.
> Fortunately no damage to her, but the derailleur is junk, the wheel
> needs re-spoking and the hanger is bent. There is a pic of the hanger
> at: http://www.westiesd.com/posting/hanger.jpg
>
> My question is, is straightening the hanger a repair best left to a
> highly trained bike mechanic, or might I be able to just bend it back
> into shape. I'm fairly good with tools but if there's a chance of my
> making a mess of the job, I'd prefer to leave it to a pro. The bike
> is a Bianchi Veloce triple.
>
> Thanks very much.
>
> Dave