derailleur hangers - bends on its own???

Discussion in 'Cycling Equipment' started by Wle, Dec 17, 2003.

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  1. Wle

    Wle Guest

    so what makes rear derailleur hangers bend?

    yesterday i noticed my indexed gears were no longer indexed.

    the chain was jumping between gears.

    tried to shift to lowest gear, didn;t get all the way before the idler wheel started hitting spokes,
    backed out of that before too late.

    got home, the derailleur hanger was bent.

    but - no crash, nothing happened.

    i do remember a mis-shifting incident, but that had been 20 miles before anything seemed wrong.

    i was going up a steep hill, in smallest front ring, wanted to move to bigger rear gear, so
    tried to shift.

    the hill was steep, i was going slow, anyway, i shouldn;t have done it but i did, it didn;t shift
    for a couple seconds, because i was going so slowly, then it made kind of a 'graunch' kind of noise,
    by then i had to stop and get off.

    but as far as i know, and i rode 10 more miles to work, nothing was wrong at the time.

    then 10 miles into the return trip, suddenly the chain is jumping, the lowest gear wants to go into
    the spokes, and i get home to check, the hanger is bent..

    can a bad shift like that, bend things?

    i have had, on my other bike, the same thing happen, that is, suddenly the hanger is bent but i
    can;t really remember doing anything, certainly no crashes.

    what forces are on this thing under normal and abnormal [but non crash] conditions?

    and, if it were strong enough to resist non-crash spontaneous bends, would it be weak enough to
    protect the frame in a real crash?

    ??, wle.
     
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  2. Werehatrack

    Werehatrack Guest

    On 17 Dec 2003 08:23:51 -0800, [email protected] (wle) may have said:

    >so what makes rear derailleur hangers bend?
    >
    >yesterday i noticed my indexed gears were no longer indexed.
    >
    >the chain was jumping between gears.
    >
    >tried to shift to lowest gear, didn;t get all the way before the idler wheel started hitting
    >spokes, backed out of that before too late.
    >
    >got home, the derailleur hanger was bent.
    >
    >but - no crash, nothing happened.

    Under similar circumstances earlier this year, I had a bent hanger after a bike did much the same
    thing...but the problem in that case was that the der had not been properly serviced by the lbs that
    had just seen it, and the pivots were *very* stiff due to old, congealed lube. I don't recall the
    exact sequence of events, but the result was the same; went for low gear, got spokes.

    Check the freedom of motion of the der pivots with the bike at outdoor riding temp. If any are
    binding or sticking (which could easily be precipitated by cold weather) then you've found
    your cause.

    --
    My email address is antispammed; pull WEEDS if replying via e-mail.
    Yes, I have a killfile. If I don't respond to something,
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  3. Wle

    Wle Guest

    > Check the freedom of motion of the der pivots with the bike at outdoor riding temp. If any are
    > binding or sticking (which could easily be precipitated by cold weather) then you've found
    > your cause.

    no, it had been colder in the morning.

    no recent work on the bike.

    what i am asking is, is there any shift-related event that can bend the derailleur hanger?

    i mean, the worst you could do would be to go crank on a shifter without pedaling, or pedaling
    slowly, the chain could get at a weird angle, with that plus a lot of pedal pressure, would that
    lone bend the hanger?

    i have read that, nothing bends them but a crash, yet i have had mine bent at least 3 times, no
    crashes. normally i don;t do extreme shifts like the one that may have caused this one either.

    even if i caused it, it took 20 more riding miles to exhibit any evidence.. what kind of sense does
    that make?

    wle.
     
  4. Werehatrack

    Werehatrack Guest

    On 18 Dec 2003 20:36:00 -0800, [email protected] (wle) may have said:

    >> Check the freedom of motion of the der pivots with the bike at outdoor riding temp. If any are
    >> binding or sticking (which could easily be precipitated by cold weather) then you've found
    >> your cause.
    >
    >no, it had been colder in the morning.
    >
    >no recent work on the bike.
    >
    >what i am asking is, is there any shift-related event that can bend the derailleur hanger?

    No normal shifter motion will bend the hanger.

    >i mean, the worst you could do would be to go crank on a shifter without pedaling, or pedaling
    >slowly, the chain could get at a weird angle, with that plus a lot of pedal pressure, would that
    >lone bend the hanger?

    No.

    >i have read that, nothing bends them but a crash, yet i have had mine bent at least 3 times, no
    >crashes. normally i don;t do extreme shifts like the one that may have caused this one either.

    I've had two bends due to non-crash incidents. One was the sticking pivot problem that I described
    earlier, the other was due to a der failure which also put the jockey wheels into the spokes.

    >even if i caused it, it took 20 more riding miles to exhibit any evidence.. what kind of sense does
    >that make?

    It sounds just like what happened when I had the sticking pivot.

    --
    My email address is antispammed; pull WEEDS if replying via e-mail.
    Yes, I have a killfile. If I don't respond to something,
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  5. G.Daniels

    G.Daniels Guest

    outa whack? the hanger canbe adjusted with or by a 6" plus grip channel locks or pipe wrench.
    buyastringandgetthe hang ofyeballingthe
    chain/gears/cluster/frameitsavisualproblemthatsneedsadjsutingtoo. the rig, and i ride
    friction levers, goes outawhack slowly over 200 miles or so then doesn't work so good then
    doesn't work at all.
     
  6. Wle

    Wle Guest

    Werehatrack <[email protected]> wrote in message news:<[email protected]>...
    > On 18 Dec 2003 20:36:00 -0800, [email protected] (wle) may have said:
    >
    > >> Check the freedom of motion of the der pivots with the bike at outdoor riding temp. If any are
    > >> binding or sticking (which could easily be precipitated by cold weather) then you've found your
    > >> cause.
    > >
    > >no, it had been colder in the morning.
    > >
    > >no recent work on the bike.
    > >
    > >what i am asking is, is there any shift-related event that can bend the derailleur hanger?
    >
    > No normal shifter motion will bend the hanger.
    >
    > >i mean, the worst you could do would be to go crank on a shifter without pedaling, or pedaling
    > >slowly, the chain could get at a weird angle, with that plus a lot of pedal pressure, would that
    > >lone bend the hanger?
    >
    > No.
    >
    > >i have read that, nothing bends them but a crash, yet i have had mine bent at least 3 times, no
    > >crashes. normally i don;t do extreme shifts like the one that may have caused this one either.
    >
    > I've had two bends due to non-crash incidents. One was the sticking pivot problem that I described
    > earlier, the other was due to a der failure which also put the jockey wheels into the spokes.

    >
    > >even if i caused it, it took 20 more riding miles to exhibit any evidence.. what kind of sense
    > >does that make?
    >
    > It sounds just like what happened when I had the sticking pivot.

    but - what is the difference between sticky pivots, and
    trying to jam the chain over when it doesn;t want to go?

    either way, the result is a lot of unresolved force from the cable side.

    are you saying this force bent your hanger?

    wle.
     
  7. wle wrote:
    > Werehatrack <[email protected]> wrote in message
    > news:<[email protected]>...
    >> On 18 Dec 2003 20:36:00 -0800, [email protected] (wle) may have said:
    >>
    >>>> Check the freedom of motion of the der pivots with the bike at outdoor riding temp. If any are
    >>>> binding or sticking (which could easily be precipitated by cold weather) then you've found your
    >>>> cause.
    >>>
    >>> no, it had been colder in the morning.
    >>>
    >>> no recent work on the bike.
    >>>
    >>> what i am asking is, is there any shift-related event that can bend the derailleur hanger?
    >>
    >> No normal shifter motion will bend the hanger.
    >>
    >>> i mean, the worst you could do would be to go crank on a shifter without pedaling, or pedaling
    >>> slowly, the chain could get at a weird angle, with that plus a lot of pedal pressure, would that
    >>> lone bend the hanger?
    >>
    >> No.
    >>
    >>> i have read that, nothing bends them but a crash, yet i have had mine bent at least 3 times, no
    >>> crashes. normally i don;t do extreme shifts like the one that may have caused this one either.
    >>
    >> I've had two bends due to non-crash incidents. One was the sticking pivot problem that I
    >> described earlier, the other was due to a der failure which also put the jockey wheels into the
    >> spokes.
    >
    >>
    >>> even if i caused it, it took 20 more riding miles to exhibit any evidence.. what kind of sense
    >>> does that make?
    >>
    >> It sounds just like what happened when I had the sticking pivot.
    >
    >
    > but - what is the difference between sticky pivots, and
    > trying to jam the chain over when it doesn;t want to go?
    >
    > either way, the result is a lot of unresolved force from the cable side.
    >
    > are you saying this force bent your hanger?
    >
    > wle.

    I bent mine once leaning the bike up against a fence a little carelessly. Maybe somebody bumped into
    the bike while I was having my coffee.
    --
    Perre

    You have to be smarter than a robot to reply.
     
  8. wle <[email protected]> wrote:

    > what i am asking is, is there any shift-related event that can bend the derailleur hanger?

    Yeah, if you shift while crushing on the pedals, it can cause drivetrain problems - bent chain
    links, bent derailleur, bent der hanger.

    In the "old days" [tm], you always had to lighten up on the pedals just a bit while shifting. With
    new drivetrain parts and shaped rings and cogs that allow easier chain derailment, a lighter touch
    is not necessary to shift, but it is still a good idea.

    Once the der hanger is bent, it is probably easier for it to get bent again (depending on material).
     
  9. Werehatrack

    Werehatrack Guest

    On 19 Dec 2003 07:30:07 -0800, [email protected] (wle) may have said:

    > but - what is the difference between sticky pivots, and
    > trying to jam the chain over when it doesn;t want to go?

    A properly adjusted derailleur will not leave its normal operational position ranges just because
    you pull on the cable with the chain stopped. But when a pivot sticks while you're shifting *with*
    pedalling, the jockey wheels *may* get into areas where they should not be, and *may* grab the
    spokes. The cable isn't the culprit, the out-of-bounds motion of the der is. When you try to force
    the der while stopped, almost no motion will occur, therefore not out-of-bounds motion will, either.

    >either way, the result is a lot of unresolved force from the cable side.

    Which the der is quite capable of ignoring.

    >are you saying this force bent your hanger?

    No, the bloody huge wrenching of the whole mess around with the wheel when the end of the der
    grabbed a spoke is what bent it. No force that the *cable* can exert will bend the hanger. But if
    things aren't ring in the ser, in shifting. the der can get tangled with the spokes, and *that* will
    bend the hanger. It can't happen unless the wheel and chain are in motion to swing the der into the
    path of a moving spoke. Not all rear ders will allow a der/spoke collision, but many will, and aside
    from an impact, that's the only way I've seen for a bent hanger to result.

    --
    My email address is antispammed; pull WEEDS if replying via e-mail.
    Yes, I have a killfile. If I don't respond to something,
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