Rebending steel dropouts

Discussion in 'Cycling Equipment' started by meb, Jan 16, 2005.

  1. meb

    meb New Member

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    I had my rder shatter a hole in my plastic spoke protector as it went through it enroute to getting trapped in my spokes. Not sure if the freewheel bearings snagged first (I had suspicions the bearings were starting to go) or the axle bent first, but suspect the former. At any rate, the left dropout is bent open (bicycle pitch axis, slightly lateral). It’s a steel framed mountain bike, my low end beater. If I re-bend the dropouts back to original shape, are they likely to be weakened so as to be prone to failure?
     
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  2. It depends on how cheap a frame. I wouldn't trust doing
    it to a department store frame. I have done it two years ago to a old
    late 80s Schwinn and early 90s GT frame with no problems.
     
  3. ahimsa

    ahimsa New Member

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    No, I'd say you're pretty safe. Especially if it is your beater bike. I've rebent plenty of dropouts like that on Wal*Mart bikes in the shop for kids, and they keep on riding them into the ground. Steel is resilient like that. More power to you.
     
  4. Werehatrack

    Werehatrack Guest

    On Sun, 16 Jan 2005 20:58:07 +1100, meb
    <[email protected]> may have said:

    >
    >I had my rder shatter a hole in my plastic spoke protector as it went
    >through it enroute to getting trapped in my spokes. Not sure if the
    >freewheel bearings snagged first (I had suspicions the bearings were
    >starting to go) or the axle bent first, but suspect the former.


    It's a possibility, but check the der for a sticky pivot before you
    ride it again. That's just one of several things that can put the
    cage into the spokes.

    > At any
    >rate, the left dropout is bent open (bicycle pitch axis, slightly
    >lateral). It’s a steel framed mountain bike, my low end beater. If I
    >re-bend the dropouts back to original shape, are they likely to be
    >weakened so as to be prone to failure?


    The back end of the dropout is not the part that carries most of the
    riding stress; as long as it doesn't develop cracks when you bend it
    back, I wouldn't worry about it. Cheap beater frames tend to be more
    forgiving about this than fancy bikes, in my experience.

    --
    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.
     
  5. meb wrote:

    > I had my rder shatter a hole in my plastic spoke protector as it went
    > through it enroute to getting trapped in my spokes. Not sure if the
    > freewheel bearings snagged first (I had suspicions the bearings were
    > starting to go) or the axle bent first, but suspect the former. At any
    > rate, the left dropout is bent open (bicycle pitch axis, slightly
    > lateral). It’s a steel framed mountain bike, my low end beater. If I
    > re-bend the dropouts back to original shape, are they likely to be
    > weakened so as to be prone to failure?


    Yes, but what have you got to lose?

    I generally do this sort of repair with a monkey wrench (right-angle
    adjustable wrench) and an Inertial Impact Alignment Instrument (hammer.)

    Use the monkey wrench to help bring the bottom of the dropout into the
    correct plane while simultaneously hammering it back so that the axle
    slot becomes parallel.

    Cheapo bikes these days often come with horrible axle nuts and no
    washers between the nuts and the dropout. This is bad news in general,
    and should never be used on a dropout that has been bent open then
    closed up again.

    As the nut turns while pressing against the dropout it is very liable to
    force it open.

    If possible, buy a pair of proper track nuts with captive washers. If
    not, buy a pair of "serrated axle washers" to fit between the nuts and
    the dropouts, or convert to quick release.

    Sheldon "Nuts" Brown
    +------------------------------------+
    | Immigrants are not our burden, |
    | They are our wealth --Jane Adams |
    +------------------------------------+
    Harris Cyclery, West Newton, Massachusetts
    Phone 617-244-9772 FAX 617-244-1041
    http://harriscyclery.com
    Hard-to-find parts shipped Worldwide
    http://captainbike.com http://sheldonbrown.com
     
  6. Werehatrack

    Werehatrack Guest

    On Sun, 16 Jan 2005 12:07:59 -0500, Sheldon Brown
    <[email protected]> may have said:

    >Cheapo bikes these days often come with horrible axle nuts and no
    >washers between the nuts and the dropout.


    I suspect that you may be referring to the ones with the lovely
    serrated flanges that are unsurpassed in their ability to tear up the
    surface of the dropout. (I've seen some even less useful nuts used as
    well, though, such as the ones with a waffled face on the end of the
    hex.)

    >This is bad news in general,
    >and should never be used on a dropout that has been bent open then
    >closed up again.
    >
    >As the nut turns while pressing against the dropout it is very liable to
    >force it open.


    Teeth grab, transferring torque as lateral force shoving the dropout
    open, yup, BTDT, even on a dropout that had not previously been fouled
    as far as I could tell. It was on a bike that Huffy would have called
    "crude".

    >If possible, buy a pair of proper track nuts with captive washers. If
    >not, buy a pair of "serrated axle washers" to fit between the nuts and
    >the dropouts,


    I recall that a discussion of track nuts earlier in the week produced
    the information that loose-flange nuts with a 24tpi threading were not
    to be had. If that's 3/8-24, I will note that a dig through my Olde
    Hardware Boxe turned up exactly one such bit; I don't have a clue what
    it was originally used on, but there it was. (It's amazing what 35
    years of mechanical packratting can produce at times.)

    In the past, when really annoyed by the perversity of machinery, I
    have created such loose-flange nuts by finding a washer that was thick
    enough to be useful and cutting a shoulder into the nut to allow it to
    center in the bore of the washer. The trick is having a sufficiently
    large selection of washers to choose from. Cutting the shoulder is
    usually no trouble at all; it can be done on a drill press with a
    couple of carefully selected sharp files, among other ways.

    >or convert to quick release.


    Alas, there is one situation in which even this is not an option; the
    aforementioned coaster brake...but you knew that. Coasters are, of
    course, not exactly the center of a lot of high-tech development and
    intensive boutique design marketing, so it's hardly surprising that
    the support for unusual requirements involving them is meager.




    --
    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.
     
  7. Tom Sherman

    Tom Sherman Guest

    Sheldon "Nuts" Brown wrote:

    > ...
    > Cheapo bikes these days often come with horrible axle nuts and no
    > washers between the nuts and the dropout. This is bad news in general,
    > and should never be used on a dropout that has been bent open then
    > closed up again.
    >
    > As the nut turns while pressing against the dropout it is very liable to
    > force it open.
    >
    > If possible, buy a pair of proper track nuts with captive washers. If
    > not, buy a pair of "serrated axle washers" to fit between the nuts and
    > the dropouts, or convert to quick release....


    Sheldon,

    Are the nuts SRAM and Shimano supply with their internally geared hubs
    acceptable? What about the "BOB Nutz" [1] for use with internally geared
    hubs and BOB trailers?

    [1] <http://www.bobtrailers.com/accessories/bobnutz.php>.

    --
    Tom Sherman - Near Rock Island
     
  8. On 2005-01-16, meb <[email protected]> wrote:

    > I had my rder shatter a hole in my plastic spoke protector as it went
    > through it enroute to getting trapped in my spokes. Not sure if the
    > freewheel bearings snagged first (I had suspicions the bearings were
    > starting to go) or the axle bent first, but suspect the former. At any
    > rate, the left dropout is bent open (bicycle pitch axis, slightly
    > lateral). It’s a steel framed mountain bike, my low end beater. If I
    > re-bend the dropouts back to original shape, are they likely to be
    > weakened so as to be prone to failure?


    Most dropouts are forged from mild steel to accommodate just this sort of
    thing. The exception would be investment cast dropouts, which may be less
    forgiving of rebending.

    --

    -John ([email protected])
     
  9. John Thompson wrote:

    > Most dropouts are forged from mild steel to accommodate just this sort of
    > thing. The exception would be investment cast dropouts, which may be less
    > forgiving of rebending.


    Actually, most dropouts are _stamped_ from sheet metal. Only high-end
    bikes have forged or investment-cast dropouts.

    Sheldon "Wish It Were So" Brown
    +---------------------------------------------+
    | Television: |
    | A medium. So called because it is |
    | neither rare nor well done. |
    | --Ernie Kovacs |
    +---------------------------------------------+
    Harris Cyclery, West Newton, Massachusetts
    Phone 617-244-9772 FAX 617-244-1041
    http://harriscyclery.com
    Hard-to-find parts shipped Worldwide
    http://captainbike.com http://sheldonbrown.com
     
  10. I wrote:
    >>Cheapo bikes these days often come with horrible axle nuts and no
    >>washers between the nuts and the dropout.

    >

    Someone who turns into a headgear storage device when the moon is full
    wrote:
    >
    > I suspect that you may be referring to the ones with the lovely
    > serrated flanges that are unsurpassed in their ability to tear up the
    > surface of the dropout. (I've seen some even less useful nuts used as
    > well, though, such as the ones with a waffled face on the end of the
    > hex.)
    >

    I was not referring exclusively to those, but to _any_ nut used without
    a washer.
    >
    >>If possible, buy a pair of proper track nuts with captive washers. If
    >>not, buy a pair of "serrated axle washers" to fit between the nuts and
    >>the dropouts,


    > In the past, when really annoyed by the perversity of machinery, I
    > have created such loose-flange nuts by finding a washer that was thick
    > enough to be useful and cutting a shoulder into the nut to allow it to
    > center in the bore of the washer. The trick is having a sufficiently
    > large selection of washers to choose from. Cutting the shoulder is
    > usually no trouble at all; it can be done on a drill press with a
    > couple of carefully selected sharp files, among other ways.


    This is a LOT of trouble to go to. If you can't get track nuts to fit
    your axle, just use serrated axle washers (a standard bicycle part.)

    They're just as secure. The only advantage of the track nuts is that
    they make wheel installation a wee bit faster, since they stay with the
    nuts. With loose washers, you just have to make sure to place the
    washers on the outsides of the dropouts.
    >
    >>or convert to quick release.

    >
    > Alas, there is one situation in which even this is not an option; the
    > aforementioned coaster brake...but you knew that. Coasters are, of
    > course, not exactly the center of a lot of high-tech development and
    > intensive boutique design marketing, so it's hardly surprising that
    > the support for unusual requirements involving them is meager.


    Actually, there's no inherent reason you couldn't use a quick release
    with a coaster brake, but you'd need to source a hollow axle with the
    correct threading. That might not be so easy.

    Tom Sherman queried:

    > Are the nuts SRAM and Shimano supply with their internally geared hubs
    > acceptable? What about the "BOB Nutz" [1] for use with internally
    > geared hubs and BOB trailers?


    Any of these are fine, as long as appropriate serrated washers are used
    with them. If the hubs have serrated surfaces on the cone locknuts, you
    can even sometimes get by with flat washers.

    What's bad is nuts rotating directly against the dropout.

    Sheldon "Not That Difficult" Brown
    +------------------------------------+
    | Experience is a hard teacher, |
    | because she gives the test first, |
    | the lesson after. -- Vernon Law |
    +------------------------------------+
    Harris Cyclery, West Newton, Massachusetts
    Phone 617-244-9772 FAX 617-244-1041
    http://harriscyclery.com
    Hard-to-find parts shipped Worldwide
    http://captainbike.com http://sheldonbrown.com
     
  11. jim beam

    jim beam Guest

    John Thompson wrote:
    > On 2005-01-16, meb <[email protected]> wrote:
    >
    >
    >>I had my rder shatter a hole in my plastic spoke protector as it went
    >>through it enroute to getting trapped in my spokes. Not sure if the
    >>freewheel bearings snagged first (I had suspicions the bearings were
    >>starting to go) or the axle bent first, but suspect the former. At any
    >>rate, the left dropout is bent open (bicycle pitch axis, slightly
    >>lateral). It’s a steel framed mountain bike, my low end beater. If I
    >>re-bend the dropouts back to original shape, are they likely to be
    >>weakened so as to be prone to failure?

    >
    >
    > Most dropouts are forged from mild steel to accommodate just this sort of
    > thing. The exception would be investment cast dropouts, which may be less
    > forgiving of rebending.
    >

    just like sheldon says, most dropouts are stamped from sheet and easily
    bendable. the quality stuff is investment cast [good] or forged
    [better]. both are easily destinguished from stamped. forged should be
    able to take more abuse than investment cast [although some cast
    dropouts are very good indeed].
     
  12. Werehatrack

    Werehatrack Guest

    On Sun, 16 Jan 2005 16:34:32 -0500, Sheldon Brown
    <[email protected]> may have said:

    >I wrote:
    >>>Cheapo bikes these days often come with horrible axle nuts and no
    >>>washers between the nuts and the dropout.

    >>

    >Someone who turns into a headgear storage device when the moon is full
    >wrote:
    >>
    >> In the past, when really annoyed by the perversity of machinery, I
    >> have created such loose-flange nuts...

    >
    >This is a LOT of trouble to go to. If you can't get track nuts to fit
    >your axle, just use serrated axle washers (a standard bicycle part.)


    That works well if the threaded stub is long enough, but sometimes
    I've had to work with a non-replaceable existing stud that presented
    only six or seven lands of thread for the nut to begin with; in that
    instance, making a stepped nut that would go inside a thick washer
    allowed the contact surface to be much larger while still getting
    enough of a grip on the stud. The only time I went to this extreme
    with a bike was when I was installing a set of old-style rear baskets
    (with the thick, heavy supports that went to the axle rather than the
    dropout tabs) on a historic 3-speed. The original waffle-washer got
    counterbored, and the nut shouldered to match. It wasn't the fastest
    solution, but it certainly held up well.

    >Actually, there's no inherent reason you couldn't use a quick release
    >with a coaster brake, but you'd need to source a hollow axle with the
    >correct threading. That might not be so easy.


    Ayup.

    --
    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.
     
  13. A Muzi

    A Muzi Guest

    meb wrote:
    > I had my rder shatter a hole in my plastic spoke protector as it went
    > through it enroute to getting trapped in my spokes. Not sure if the
    > freewheel bearings snagged first (I had suspicions the bearings were
    > starting to go) or the axle bent first, but suspect the former. At any
    > rate, the left dropout is bent open (bicycle pitch axis, slightly
    > lateral). It’s a steel framed mountain bike, my low end beater. If I
    > re-bend the dropouts back to original shape, are they likely to be
    > weakened so as to be prone to failure?


    For steel frames, the cheaper it is, the more likely it is
    to survive unscathed. You can't do this:
    http://www.yellowjersey.org/brnn.html

    to a premium quality frame - it would fail.
    And aluminum is almost certain not to survive such
    rebending.

    Actually cheap bikes tell some amazing tales:
    http://www.yellowjersey.org/photosfromthepast/NIMGAFRK.JPG

    which would have been fatal to thinner walled, harder materials.
    --
    Andrew Muzi
    www.yellowjersey.org
    Open every day since 1 April, 1971
     
  14. Werehatrack

    Werehatrack Guest

    On Mon, 17 Jan 2005 18:07:50 GMT, John Thompson
    <[email protected]> may have said:

    >On 2005-01-17, Werehatrack <[email protected]> wrote:
    >
    >>Sheldon Brown wrote:
    >>>Actually, there's no inherent reason you couldn't use a quick release
    >>>with a coaster brake, but you'd need to source a hollow axle with the
    >>>correct threading. That might not be so easy.

    >>
    >> Ayup.

    >
    >Not to mention the fact that the reaction arm makes the very notion of
    >"quick release" superfluous on such a hub...


    Shorten up the bolt from a quick-release seat clamp, slot the reaction
    arm, and you could QR that spot as well.

    Of course, the real question would remain "why?"

    --
    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.
     
  15. On Mon, 17 Jan 2005 18:48:35 -0600, Werehatrack
    <[email protected]> wrote:

    >On Mon, 17 Jan 2005 18:07:50 GMT, John Thompson
    ><[email protected]> may have said:
    >
    >>On 2005-01-17, Werehatrack <[email protected]> wrote:
    >>
    >>>Sheldon Brown wrote:
    >>>>Actually, there's no inherent reason you couldn't use a quick release
    >>>>with a coaster brake, but you'd need to source a hollow axle with the
    >>>>correct threading. That might not be so easy.
    >>>
    >>> Ayup.

    >>
    >>Not to mention the fact that the reaction arm makes the very notion of
    >>"quick release" superfluous on such a hub...

    >
    >Shorten up the bolt from a quick-release seat clamp, slot the reaction
    >arm, and you could QR that spot as well.
    >
    >Of course, the real question would remain "why?"


    Dear Werehatrack,

    Well, a slot on the rear swing arm or on the front fork
    makes it much easier and faster to remove and reinstall
    heavy motorcycle wheels.

    Carl Fogel
     
  16. jim beam

    jim beam Guest

    David L. Johnson wrote:
    > On Mon, 17 Jan 2005 10:35:08 -0800, jim beam wrote:
    >
    >
    >
    >>>There's nothing wrong with cast dropouts, but due to the nature of
    >>>investment casting they tend to be difficult to bend and subject to
    >>>cracking with bending.
    >>>

    >>
    >>ergo, forged better than cast, which are better than stamped...

    >
    >
    > Aren't the old Campagnolo dropouts used on the best frames of the 60's and
    > early 70's investment cast? Or are they forged? I've never had to
    > straighten one, but wonder what these are.
    >

    forged. the high quality investment casting you see today is a
    relatively recent phenomenon.
     
  17. A Muzi

    A Muzi Guest

    >>>There's nothing wrong with cast dropouts, but due to the nature of
    >>>investment casting they tend to be difficult to bend and subject to
    >>>cracking with bending.


    > On Mon, 17 Jan 2005 10:35:08 -0800, jim beam wrote:
    >>ergo, forged better than cast, which are better than stamped...


    David L. Johnson wrote:
    > Aren't the old Campagnolo dropouts used on the best frames of the 60's and
    > early 70's investment czast? Or are they forged? I've never had to
    > straighten one, but wonder what these are.


    The old long Campagnolo 1010 ends with the eye lets were
    indeed forged, as were the first models of shorter 1010/B
    in the middle seventies. About 1981 or so these changed to
    a cast SCM part. Shimano made a similar change. Both
    brands showed an increase in failures just behind the
    chainstay joint and across the web (both ends).

    A short lived trend to massive, socketed cast CrMo steel
    frame ends faded in favor of both miniature verticals and
    alternate materials.

    --
    Andrew Muzi
    www.yellowjersey.org
    Open every day since 1 April, 1971
     
  18. A Muzi

    A Muzi Guest

    >>>There's nothing wrong with cast dropouts, but due to the nature of
    >>>investment casting they tend to be difficult to bend and subject to
    >>>cracking with bending.


    > On Mon, 17 Jan 2005 10:35:08 -0800, jim beam wrote:
    >>ergo, forged better than cast, which are better than stamped...


    David L. Johnson wrote:
    > Aren't the old Campagnolo dropouts used on the best frames of the 60's and
    > early 70's investment czast? Or are they forged? I've never had to
    > straighten one, but wonder what these are.


    The old long Campagnolo 1010 ends with the eye lets were
    indeed forged, as were the first models of shorter 1010/B
    in the middle seventies. About 1981 or so these changed to
    a cast SCM part. Shimano made a similar change. Both
    brands showed an increase in failures just behind the
    chainstay joint and across the web (both ends).

    A short lived trend to massive, socketed cast CrMo steel
    frame ends faded in favor of both miniature verticals and
    alternate materials.

    --
    Andrew Muzi
    www.yellowjersey.org
    Open every day since 1 April, 1971
     
  19. On 2005-01-17, David L. Johnson <[email protected]> wrote:

    > Aren't the old Campagnolo dropouts used on the best frames of the 60's and
    > early 70's investment cast? Or are they forged? I've never had to
    > straighten one, but wonder what these are.


    Nope, they're forged mild steel.

    --

    -John (john[email protected])
     
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