Bent spoke needs replacing?

Discussion in 'Cycling Equipment' started by Wayne Pein, May 25, 2004.

  1. Wayne Pein

    Wayne Pein Guest

    In a race another cyclist crashed into me, causing me to go down.
    Something, possibly a skewer or pedal, from his bike apparently broke a
    rear spoke of mine near its midpoint. Another spoke has a couple of
    closely spaced minor bends. When I rub my fingers over it I can feel it.

    Does this spoke need to be replaced?

    Thanks,
    Wayne
     
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  2. daveornee

    daveornee Guest

    Wayne Pein wrote:
    > In a race another cyclist crashed into me, causing me to go down.
    > Something, possibly a skewer or pedal, from his bike apparently broke a
    > rear spoke of mine near its midpoint. Another spoke has a couple of
    > closely spaced minor bends. When I rub my fingers over it I can feel it.
    > Does this spoke need to be replaced?
    > Thanks, Wayne




    Yes, although it might last for thousands of miles. I wouldn't take
    the risk when the cost is this low. That spoke would be operating
    at a higher tension and carrying more of the load. Truing the wheel
    with a kinked spoke results in a sub-optimal wheel. All spokes
    shold run straight as a string stretched from the top of the nipple
    to the hub hole.



    --
     
  3. Doug Huffman

    Doug Huffman Guest

    Kind'a like the elbow? A kinky bend that lasts and lasts. Or the stress
    riser at the threads - that lasts and lasts.

    As to 'string', whattabout the bend at the crossings?


    "daveornee" <[email protected]> wrote in message
    news:[email protected]
    | Wayne Pein wrote:
    | > In a race another cyclist crashed into me, causing me to go down.
    | > Something, possibly a skewer or pedal, from his bike apparently broke
    a
    | > rear spoke of mine near its midpoint. Another spoke has a couple of
    | > closely spaced minor bends. When I rub my fingers over it I can feel
    it.
    | > Does this spoke need to be replaced?
    | > Thanks, Wayne
    |
    |
    |
    | Yes, although it might last for thousands of miles. I wouldn't take
    | the risk when the cost is this low. That spoke would be operating
    | at a higher tension and carrying more of the load. Truing the wheel
    | with a kinked spoke results in a sub-optimal wheel. All spokes
    | shold run straight as a string stretched from the top of the nipple
    | to the hub hole.
    |
    |
    |
    | --
    |
    |
     
  4. Bill Lloyd

    Bill Lloyd Guest

    On 2004-05-25 09:30:07 -0700, daveornee <[email protected]> said:

    > Wayne Pein wrote:
    > > In a race another cyclist crashed into me, causing me to go down.
    > > Something, possibly a skewer or pedal, from his bike apparently broke a
    > > rear spoke of mine near its midpoint. Another spoke has a couple of
    > > closely spaced minor bends. When I rub my fingers over it I can feel it.
    > > Does this spoke need to be replaced?
    > > Thanks, Wayne

    >
    >
    >
    > Yes, although it might last for thousands of miles. I wouldn't take
    > the risk when the cost is this low. That spoke would be operating
    > at a higher tension and carrying more of the load. Truing the wheel
    > with a kinked spoke results in a sub-optimal wheel. All spokes
    > shold run straight as a string stretched from the top of the nipple
    > to the hub hole.


    I disagree. The bent spoke isn't really stretched or tensioned all
    that differently. If there's not a visible nick in the spoke, and it
    just a little kink, I don't think it's a bad idea.

    I have plenty of wheels that have spokes that have bends in them from
    race crashes. I've never had a spoke fail at one of those points...
    all spoke failures I've had have been at the elbows (one wheel, the
    flange doesn't support the spokes properly), or from heads popping off
    the spokes (bad drill job in the hub flange).
     
  5. Wayne Pein writes:

    > In a race another cyclist crashed into me, causing me to go down.
    > Something, possibly a skewer or pedal, from his bike apparently
    > broke a rear spoke of mine near its midpoint. Another spoke has a
    > couple of closely spaced minor bends. When I rub my fingers over it
    > I can feel it.


    > Does this spoke need to be replaced?


    Yes. Spokes that I broke recently had, on close inspections, kinks
    from airline shipping where they threw the bicycle to the ground by
    missing the baggage cart (by accident). Baggage mashers at airlines
    hate bicycles and don't treat them well.

    Anyway, such kinks have residual stress and also flex with each wheel
    revolution. In a bind, the spoke could be hammered straight in place
    and subsequently stress relieved. My kinks were first noticed when
    the spoke broke a few thousand miles later. Last year these guys
    ripped one of the spokes out of the wheel so that the nipple broke
    rather than the rim. I was lucky.

    This is a reason to use a bicycle suitcase. I have always used a soft
    cover over the broken down bicycle because I can carry it in one hand
    with my suitcase in the other when taking trains from the airport.

    Jobst Brandt
    [email protected]
     
  6. Wayne Pein

    Wayne Pein Guest

    Wayne Pein wrote:

    > In a race another cyclist crashed into me, causing me to go down.
    > Something, possibly a skewer or pedal, from his bike apparently broke a
    > rear spoke of mine near its midpoint. Another spoke has a couple of
    > closely spaced minor bends. When I rub my fingers over it I can feel it.
    >
    > Does this spoke need to be replaced?
    >
    > Thanks,
    > Wayne


    Thanks to all who responded.

    Wayne
     
  7. Werehatrack

    Werehatrack Guest

    On Tue, 25 May 2004 16:05:27 GMT, Wayne Pein <[email protected]> may
    have said:

    >In a race another cyclist crashed into me, causing me to go down.
    >Something, possibly a skewer or pedal, from his bike apparently broke a
    >rear spoke of mine near its midpoint. Another spoke has a couple of
    >closely spaced minor bends. When I rub my fingers over it I can feel it.
    >
    >Does this spoke need to be replaced?


    I would replace it. I suspect that the wheel will be out of true at
    the location of that spoke; this should be a hint that it's either
    under added tension, or it's stretched and not under correct tension
    anymore. Would you build a wheel using a bent spoke on purpose? No.
    Then why leave one in when you have another to replace anyway?



    --
    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.
     
  8. daveornee

    daveornee Guest

    Doug Huffman wrote:
    > Kind'a like the elbow? A kinky bend that lasts and lasts. Or the stress
    > riser at the threads - that lasts and lasts.
    > As to 'string', whattabout the bend at the crossings? <SNIP>
    > |
    > |




    The spokes should run straight from the crossing in both directions.

    Take a look at how Sheldon Brown suggests stress relieving. I don't use
    his "stress relieving" method, as such, but I use it for spoke alignment
    at spoke crossings.

    <http://sheldonbrown.com/wheelbuild.html>

    Since the shortest distance between two points is a strainght line,
    spokes handle the dynamic loads best when they are all straight.



    --
     
  9. daveornee <[email protected]> wrote:
    > The spokes should run straight from the crossing in both directions.
    >
    > Take a look at how Sheldon Brown suggests stress relieving. I don't use
    > his "stress relieving" method, as such, but I use it for spoke alignment
    > at spoke crossings.


    this method bends the spoke at the place of contact between the old crank
    and the point on the spoke closest to the cross (especially on high tension
    wheels -- ie, rear drive side). it's pretty slight but even using a
    small force it's still there and you can feel it if you run your finger
    along the length of the spoke. is that not a problem? or is it strangely
    just me?
    --
    david reuteler
    [email protected]
     
  10. David Reuteler writes:

    >> The spokes should run straight from the crossing in both directions.


    This is not necessary, the bend being insufficient to cause
    significant stress. I have not seen a spoke break at this point even
    though my ancient spokes have distinct fretting notches at that point.

    >> Take a look at how Sheldon Brown suggests stress relieving. I
    >> don't use his "stress relieving" method, as such, but I use it for
    >> spoke alignment at spoke crossings.


    > This method bends the spoke at the place of contact between the old
    > crank and the point on the spoke closest to the cross (especially on
    > high tension wheels -- ie, rear drive side). It's pretty slight but
    > even using a small force it's still there and you can feel it if you
    > run your finger along the length of the spoke. Is that not a
    > problem, or is it strangely just me?


    I don't recommend this method for that reason and because it is too
    close to the hub where it introduces large side loads. Manual
    over-tensioning with leather work gloves cannot cause kinks in spokes
    and it is adequate if done forcefully. The crank in the spokes method
    can exceed tension levels that are beneficial to spokes and can be
    damaging to hubs where excess stress in spoke holes is not visible or
    detectable until failure.

    Jobst Brandt
    [email protected]
     
  11. daveornee

    daveornee Guest

    David Reuteler wrote:
    > daveornee <[email protected]> wrote:
    > > The spokes should run straight from the crossing in both directions.
    > >
    > > Take a look at how Sheldon Brown suggests stress relieving. I don't
    > > use his "stress relieving" method, as such, but I use it for spoke
    > > alignment at spoke crossings.

    > this method bends the spoke at the place of contact between the old
    > crank and the point on the spoke closest to the cross (especially on
    > high tension wheels -- ie, rear drive side). it's pretty slight but even
    > using a small force it's still there and you can feel it if you run your
    > finger along the length of the spoke. is that not a problem? or is it
    > strangely just me?
    > --
    > david reuteler [email protected]




    Well, I don't quite use Sheldon's exact methods and procedures either,
    but I can understand what you mean. I just took a sample of a few wheels
    that I recently built and, with my method, I only feel transitions in
    the spoke at the butts and at the actual crossings. My objective of
    straight running spokes that follow the same path as a thread stretched
    from top of nipple to hub hole, including a slight obtuse bend at the
    crossing, is attained. Spoke alignement at the hub and nipple vary
    significanly, depending on the construction of the hub and rim hole
    openings. I hope I am clear in the results and objectives... without
    going into giving the details of my methods and procedures used to
    attain them. I stand ready to be illumated by a supeior methods and
    procedures. Do we agree on the objectives?



    --
     
  12. daveornee

    daveornee Guest

    Jobst Brandt wrote:
    > David Reuteler writes:
    > >> The spokes should run straight from the crossing in both directions.

    > This is not necessary, the bend being insufficient to cause significant
    > stress. I have not seen a spoke break at this point even though my
    > ancient spokes have distinct fretting notches at that point.
    > >> Take a look at how Sheldon Brown suggests stress relieving. I don't
    > >> use his "stress relieving" method, as such, but I use it for spoke
    > >> alignment at spoke crossings.

    > > This method bends the spoke at the place of contact between the old
    > > crank and the point on the spoke closest to the cross (especially on
    > > high tension wheels -- ie, rear drive side). It's pretty slight but
    > > even using a small force it's still there and you can feel it if you
    > > run your finger along the length of the spoke. Is that not a problem,
    > > or is it strangely just me?

    > I don't recommend this method for that reason and because it is too
    > close to the hub where it introduces large side loads. Manual over-
    > tensioning with leather work gloves cannot cause kinks in spokes and it
    > is adequate if done forcefully. The crank in the spokes method can
    > exceed tension levels that are beneficial to spokes and can be damaging
    > to hubs where excess stress in spoke holes is not visible or detectable
    > until failure.
    > Jobst Brandt [email protected]




    In your book in the sectiong "Improving the spoke line" you wrote:

    "In the cross-spoked wheel, the spokes bend as they enter the hub and
    the rim. These bends should be supported at the hub by the flange and at
    the rim by the nipple. The unsuported spoke shaft should lie in a
    straight line between the last points of contact at the hub and rim. If
    there is an unsupported bend in a spoke, it will flex with changing
    loads causing fatigue and early failure."

    I have spokes that are fretting at the crossings too. My objective is to
    have the bend at the crossing move as little as possible during changing
    loads. Since the crossing spokes cause a very small change in direction,
    I apply manual forces the make a very small but very distinct bend at
    the crossing. I do this after the spokes are aligned at the hub and at
    the nipples. I have tesnioned the wheel and checked tension and tension
    balance. This manual adjustment never effects the tension balance but
    often effects tension to the point where another 1/4 turn or more is
    needed to bring the wheel back into proper tension. My reasoning for the
    distinct bend at the crossing is that the spokes will truly be following
    the shortest distance and therefore moving as little as possible in
    response to changing loads. The support that the crossing spokes provide
    to each other may help or harm the objective, but I have yet to break a
    spoke there.

    Further illumination on this topic is welcome. Did I go too far in
    attempting to attain the "Straight Line" objective?



    --
     
  13. Dave Ornee writes:

    > In your book in the section "Improving the spoke line" you wrote:


    > "In the cross-spoked wheel, the spokes bend as they enter the hub
    > and the rim. These bends should be supported at the hub by the
    > flange and at the rim by the nipple. The unsupported spoke shaft
    > should lie in a straight line between the last points of contact at
    > the hub and rim. If there is an unsupported bend in a spoke, it
    > will flex with changing loads causing fatigue and early failure."


    > I have spokes that are fretting at the crossings too. My objective
    > is to have the bend at the crossing move as little as possible
    > during changing loads. Since the crossing spokes cause a very small
    > change in direction, I apply manual forces the make a very small but
    > very distinct bend at the crossing. I do this after the spokes are
    > aligned at the hub and at the nipples. I have tensioned the wheel
    > and checked tension and tension balance. This manual adjustment
    > never effects the tension balance but often effects tension to the
    > point where another 1/4 turn or more is needed to bring the wheel
    > back into proper tension. My reasoning for the distinct bend at the
    > crossing is that the spokes will truly be following the shortest
    > distance and therefore moving as little as possible in response to
    > changing loads. The support that the crossing spokes provide to
    > each other may help or harm the objective, but I have yet to break a
    > spoke there.


    Fretting at spoke crossings is not dependent on whether the spokes
    make a gradual or abrupt bend there. Fretting is caused primarily by
    spoke elongation under torque and load, load being the larger effect.
    As I said, spokes don't break at this place even after many thousand
    miles. I have wheels that have close to 300,000 miles on their hubs
    and spokes (with replacement rims) and have not experienced a spoke
    failure at those points of contact. Spokes that broke were ones
    damaged by being kinked from foreign objects (sticks on trails) or
    baggage mashers at airports.

    > Further illumination on this topic is welcome. Did I go too far in
    > attempting to attain the "Straight Line" objective?


    I don't think the effort achieves anything useful so you could skip
    the operation on future wheels.

    Jobst Brandt
    [email protected]
     
  14. Collin

    Collin Guest

    Werehatrack wrote:

    > On Tue, 25 May 2004 16:05:27 GMT, Wayne Pein <[email protected]> may
    > have said:
    >
    >
    >>In a race another cyclist crashed into me, causing me to go down.
    >>Something, possibly a skewer or pedal, from his bike apparently broke a
    >>rear spoke of mine near its midpoint. Another spoke has a couple of
    >>closely spaced minor bends. When I rub my fingers over it I can feel it.
    >>
    >>Does this spoke need to be replaced?

    >
    >
    > I would replace it. I suspect that the wheel will be out of true at
    > the location of that spoke; this should be a hint that it's either
    > under added tension, or it's stretched and not under correct tension
    > anymore. Would you build a wheel using a bent spoke on purpose? No.
    > Then why leave one in when you have another to replace anyway?
    >
    >
    >


    Perhaps, but my bike mechanic did a very good job of recovering all of
    my spokes after an accident. His method was to flatten all of the spokes
    with a flathead screwdriver, then stress-relieve and re-true the wheel.
    It helped that he had to re-dish it anyway The wheel is now stronger
    than it was before, and the only way you can tell the spokes were
    damaged is by the scratches on them. I'm 210lbs and after about 630
    miles they're still true.

    Of course, replacing one spoke isn't very difficult. You just have to
    take the tire and wheel tape off. You will still have to true it either way.

    -Collin
     
  15. Werehatrack

    Werehatrack Guest

    On Thu, 27 May 2004 03:00:50 GMT, Collin <[email protected]> may have
    said:

    >Werehatrack wrote:
    >> ... Would you build a wheel using a bent spoke on purpose? No.
    >> Then why leave one in when you have another to replace anyway?
    >>

    >
    >Perhaps, but my bike mechanic did a very good job of recovering all of
    >my spokes after an accident. His method was to flatten all of the spokes
    >with a flathead screwdriver, then stress-relieve and re-true the wheel.


    If spokes are dear or unavailable, there's no good reason not to
    straighten and re-use ones that have only slight bends. If new ones
    are inexpensive and in hand, though, I prefer to replace.

    >It helped that he had to re-dish it anyway The wheel is now stronger
    >than it was before, and the only way you can tell the spokes were
    >damaged is by the scratches on them. I'm 210lbs and after about 630
    >miles they're still true.


    This speaks well for your wrenchman. Keep this person happy.

    >Of course, replacing one spoke isn't very difficult. You just have to
    >take the tire and wheel tape off. You will still have to true it either way.


    And since the OP had one spoke broken already, there was a good chance
    that swapping out the bent one at the same time was only going to
    require negligible additional work, or no additional work at all if
    the bent one was to be removed for straightening. One replacement
    spoke was needed anyway, so getting a second wouldn't be a lot of
    additional hassle.

    --
    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.
     
  16. jim beam

    jim beam Guest

    Doug Huffman wrote:
    > Kind'a like the elbow? A kinky bend that lasts and lasts. Or the stress
    > riser at the threads - that lasts and lasts.
    >
    > As to 'string', whattabout the bend at the crossings?


    careful doug, you'll expose a flaw in "stress relief" theory with
    heretical comments like that.

    >
    >
    > "daveornee" <[email protected]> wrote in message
    > news:[email protected]
    > | Wayne Pein wrote:
    > | > In a race another cyclist crashed into me, causing me to go down.
    > | > Something, possibly a skewer or pedal, from his bike apparently broke
    > a
    > | > rear spoke of mine near its midpoint. Another spoke has a couple of
    > | > closely spaced minor bends. When I rub my fingers over it I can feel
    > it.
    > | > Does this spoke need to be replaced?
    > | > Thanks, Wayne
    > |
    > |
    > |
    > | Yes, although it might last for thousands of miles. I wouldn't take
    > | the risk when the cost is this low. That spoke would be operating
    > | at a higher tension and carrying more of the load. Truing the wheel
    > | with a kinked spoke results in a sub-optimal wheel. All spokes
    > | shold run straight as a string stretched from the top of the nipple
    > | to the hub hole.
    > |
    > |
    > |
    > | --
    > |
    > |
    >
    >
     
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