Stress Relieving question for Jobst

Discussion in 'Cycling Equipment' started by Bill Chiarchiar, Mar 22, 2003.

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  1. Hello, Jobst,

    I'm getting ready for my first wheel building project, and I've read _the Bicycle Wheel_. I have a
    question about stress relieving.

    On page 74 of the book (3rd Edition), we see:

    Spokes are best stress relieved by grasping each of the most nearly parallel spoke pairs at
    midspan on the left and right sides of the wheel and forcefully squeezing them together
    successively around the wheel.

    Does "squeezing them together" mean squeezing the two spokes in the left pair tangentially toward
    each other while simultaneously doing the same to the two spokes in the right pair, without pressing
    the two pairs laterally (axially) towards each other? That's what I inferred, thinking that the
    simultaneous manipulation of the left and right pairs was not for pressing the two pairs towards
    each other, but rather for avoiding introduction of lateral errors.

    However, on page 106, we see:

    To stress relieve, grasp the most nearly parallel pairs of spokes at midspan on both sides of the
    wheel. Your hands should be nearly palm-to-palm. Squeeze the spokes hard.

    I wondered whether "should be nearly palm-to-palm" indicates that there should be lateral pressing.

    Which is the correct method?

    Thanks,

    Bill Chiarchiaro [email protected]
     
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  2. Jobst Brandt

    Jobst Brandt Guest

    Bill Chiarchiaro writes:

    > I wondered whether "should be nearly palm-to-palm" indicates that there should be lateral
    > pressing.

    Do you read pictures? I think the graphic, that I thought superfluous, should explain amply how to
    stretch a spoke. I guess it takes more, maybe animation.

    Jobst Brandt [email protected] Palo Alto CA
     
  3. John Albergo

    John Albergo Guest

    Bill Chiarchiaro wrote:

    >Hello, Jobst,
    >
    >I'm getting ready for my first wheel building project, and I've read _the Bicycle Wheel_. I have a
    >question about stress relieving.
    >
    >On page 74 of the book (3rd Edition), we see:
    >
    > Spokes are best stress relieved by grasping each of the most nearly parallel spoke pairs at
    > midspan on the left and right sides of the wheel and forcefully squeezing them together
    > successively around the wheel.
    >
    >Does "squeezing them together" mean squeezing the two spokes in the left pair tangentially toward
    >each other while simultaneously doing the same to the two spokes in the right pair, without
    >pressing the two pairs laterally (axially) towards each other? That's what I inferred, thinking
    >that the simultaneous manipulation of the left and right pairs was not for pressing the two pairs
    >towards each other, but rather for avoiding introduction of lateral errors.
    >
    >However, on page 106, we see:
    >
    > To stress relieve, grasp the most nearly parallel pairs of spokes at midspan on both sides of the
    > wheel. Your hands should be nearly palm-to-palm. Squeeze the spokes hard.
    >
    >I wondered whether "should be nearly palm-to-palm" indicates that there should be lateral pressing.
    >
    >Which is the correct method?
    >
    >
    I think that the phrase "nearly palm-to-palm" was used to try clarify the meaning of "most nearly
    parallel pairs of spokes". If you picked a pair on one side that was rotationally further away, your
    palms would not be facing. And the 4 spokes would not be grouped together at the rim, as they are
    when you choose the proper pairs. This may actually the point, I think. increase in tension on the
    right hand pair is counteracted by the left hand pair, so the applied force all goes into increasing
    spoke tension rather than moving the rim from side to side. Also, I think it's easier to generate
    enough (and equal) force if the hands are held out at the same distance.

    So, the palms should be "nearly facing", not "nearly touching" There's no lateral compression
    implied. You squeeze the right-side pair towards each other and the left-side pair towards
    each other.

    Also, wear some thick leather gloves when you do this otherwise it hurts like hell (or maybe I have
    tender hands).
     
  4. I have stress relieved for years and it does work, but I found that using hands I was still getting
    the odd spoke going. I started using alternative techniques, and for 700 c, I put wheel on grass and
    put a good bit of my weight on each spoke in turn with my heel. With 20 inch wheels I use a large
    screwdriver, though I've never broken a spoke in one of those. I never break spokes now.
     
  5. Joe Riel

    Joe Riel Guest

    "Gearóid Ó Laoi, Garry Lee" <[email protected]> writes:

    > With 20 inch wheels I use a large screwdriver, though I've never broken a spoke in one of those.

    Why do you do that?

    In the analysis I posted a week or so ago, I showed that the force needed to stress relieve a spoke
    is independent of its length. No one refuted it, probably it snuck under the radar...

    Joe
     
  6. Jobst Brandt responded:

    > Do you read pictures?

    I view them, but I don't read them.

    > I think the graphic, that I thought superfluous, should explain amply how to stretch a spoke.

    In fact, it did not explain amply.

    Note further that Figures 34 and 57 in _the Bicycle Wheel_, 3rd Edition, depict manipulations of
    four spokes at a time, not of "a spoke." Also, "stretch" is an unfortunate choice of word. Some
    people think that stress relieving results in macroscopic increases of spoke lengths, but on page 74
    that's claimed to be untrue.

    > I guess it takes more, maybe animation.

    Animation does not work well on the printed page. Precise writing works much better.

    Thanks to John Albergo for his followup message; I appreciate his effort. I was hoping for an answer
    from the source himself, but that evidently was an unreasonable expectation. I apologize to Jobst
    for having caused him irritation.

    Bill Chiarchiaro [email protected]
     
  7. Frank121

    Frank121 Guest

    excellent response!!!

    "Bill Chiarchiaro" <[email protected]> wrote in message
    news:[email protected]...
    > Jobst Brandt responded:
    >
    > > Do you read pictures?
    >
    > I view them, but I don't read them.
    >
    > > I think the graphic, that I thought superfluous, should explain amply how to stretch a spoke.
    >
    > In fact, it did not explain amply.
    >
    > Note further that Figures 34 and 57 in _the Bicycle Wheel_, 3rd Edition, depict manipulations of
    > four spokes at a time, not of "a spoke." Also, "stretch" is an unfortunate choice of word. Some
    > people think that stress relieving results in macroscopic increases of spoke lengths, but on page
    > 74 that's claimed to be untrue.
    >
    > > I guess it takes more, maybe animation.
    >
    > Animation does not work well on the printed page. Precise writing works much better.
    >
    > Thanks to John Albergo for his followup message; I appreciate his effort. I was hoping for an
    > answer from the source himself, but that evidently was an unreasonable expectation. I apologize to
    > Jobst for having caused him irritation.
    >
    >
    > Bill Chiarchiaro [email protected]
     
  8. [email protected] wrote in message news:<[email protected]>...
    > Bill Chiarchiaro writes:
    >
    > > I wondered whether "should be nearly palm-to-palm" indicates that there should be lateral
    > > pressing.
    >
    > Do you read pictures? I think the graphic, that I thought superfluous, should explain amply how to
    > stretch a spoke. I guess it takes more, maybe animation.
    >
    > Jobst Brandt [email protected] Palo Alto CA

    I have a question for Jobst. Is it hard going through life as such a pretentious prick? A guy asks a
    simple question to the author of a book he's reading for guidance, and instead of taking a faint few
    seconds out of your busy day to clarify a fairly simple inquiry, you instead use those same few
    seconds to belittle his request. What must it be like to be so bitter and conceited that you
    instinctively demean instead of help?
     
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