new rim bump at joint

Discussion in 'Cycling Equipment' started by Dan Daniel, Feb 21, 2004.

  1. Dan Daniel

    Dan Daniel Guest

    I built up a new rim with a pinned joint (Sun Assault, pre-welded version) and there is a slight
    offset at the joint on one side. Of course I built the wheel up so that the higher point in on the
    back side of the joint, not the front, so I have a definite 'tick' when I apply the front brake. I
    can both hear it and feel it.

    Is there a clean way to get rid of this bump, or is it best to just sit back and let the brake pads
    wear it down?

    Thanks.
     
    Tags:


  2. Jobst Brandt

    Jobst Brandt Guest

    Dan Daniel writes:

    > I built up a new rim with a pinned joint (Sun Assault, pre-welded version) and there is a slight
    > offset at the joint on one side. Of course I built the wheel up so that the higher point in on the
    > back side of the joint, not the front, so I have a definite 'tick' when I apply the front brake. I
    > can both hear it and feel it.

    > Is there a clean way to get rid of this bump, or is it best to just sit back and let the brake
    > pads wear it down?

    I can't see how large the offset is or whether it is functional or only acoustically perceptible.
    With a skilled hand and large ViseGrip pliers, the high side can be pressed down to be flush. I have
    done this with crashed rims that only had a large wow but no kinks. After much bending and
    straightening, rim joints are often not flush. Of course this is alignment is best done when tension
    is low, before final tensioning and truing.

    Jobst Brandt [email protected]
     
  3. A Muzi

    A Muzi Guest

    > Dan Daniel writes:
    >>I built up a new rim with a pinned joint (Sun Assault, pre-welded version) and there is a slight
    >>offset at the joint on one side. Of course I built the wheel up so that the higher point in on the
    >>back side of the joint, not the front, so I have a definite 'tick' when I apply the front brake. I
    >>can both hear it and feel it. Is there a clean way to get rid of this bump, or is it best to just
    >>sit back and let the brake pads wear it down?

    [email protected] wrote:
    > I can't see how large the offset is or whether it is functional or only acoustically perceptible.
    > With a skilled hand and large ViseGrip pliers, the high side can be pressed down to be flush. I
    > have done this with crashed rims that only had a large wow but no kinks. After much bending and
    > straightening, rim joints are often not flush. Of course this is alignment is best done when
    > tension is low, before final tensioning and truing.

    Yes don't be afraid to move it.

    Measure to see if the rim is the same width on both sides of the seam. They are often merely offset
    to one side at the joint. If that's the case, you can hold a rim firmly in a vise* at the joint and
    tap the free side over a slight amount, using fingers to asses progress until the joint is smooth
    and even. It's quick and straightforward to correct, certainly not a big deal.

    Occasionally you'll see a rim which is a bit narrower at one side of the seam. Hold it in a smooth
    jawed vise* and tap the crushed side back out. A judicious tap will move the edge out- a sheet metal
    tap, not a carpenter's blow.

    *But not so tightly as to change the rim's shape!

    --
    Andrew Muzi www.yellowjersey.org Open every day since 1 April, 1971
     
  4. Dan Daniel

    Dan Daniel Guest

    On Sun, 22 Feb 2004 17:59:30 -0600, A Muzi <[email protected]>
    wrote:

    >> Dan Daniel writes:
    >>>I built up a new rim with a pinned joint (Sun Assault, pre-welded version) and there is a slight
    >>>offset at the joint on one side. Of course I built the wheel up so that the higher point in on
    >>>the back side of the joint, not the front, so I have a definite 'tick' when I apply the front
    >>>brake. I can both hear it and feel it. Is there a clean way to get rid of this bump, or is it
    >>>best to just sit back and let the brake pads wear it down?
    >
    >[email protected] wrote:
    >> I can't see how large the offset is or whether it is functional or only acoustically perceptible.
    >> With a skilled hand and large ViseGrip pliers, the high side can be pressed down to be flush. I
    >> have done this with crashed rims that only had a large wow but no kinks. After much bending and
    >> straightening, rim joints are often not flush. Of course this is alignment is best done when
    >> tension is low, before final tensioning and truing.
    >

    Hmmmm.... the problem with the Sun rim is that it is epoxied. I did put it in a machinist vice with
    the intention of flattening it flush, but a couple of funny crunching noises made me stop. Maybe it
    was just the epoxy cracking and I should have kept going.

    The bump doesn't make braking dangerous. I can feel it and hear it, but that's about it.

    >Yes don't be afraid to move it.
    >
    >Measure to see if the rim is the same width on both sides of the seam. They are often merely offset
    >to one side at the joint.

    Not the case here. One side is perfectly flush, the other offset.

    >If that's the case, you can hold a rim firmly in a vise* at the joint and tap the free side over a
    >slight amount, using fingers to asses progress until the joint is smooth and even. It's quick and
    >straightforward to correct, certainly not a big deal.
    >
    >Occasionally you'll see a rim which is a bit narrower at one side of the seam. Hold it in a smooth
    >jawed vise* and tap the crushed side back out. A judicious tap will move the edge out- a sheet
    >metal tap, not a carpenter's blow.
    >

    Ah, ok, this might be possible if the epoxy isn't a killer. I hadn't thought about moving it out
    rather than bringing the larger section back in.

    >*But not so tightly as to change the rim's shape!

    Wait a minute- that's exactly what I *do* want- a new shape! :)

    Thanks to both of you. I'll try a bit more and then maybe just pull out the files and take the bump
    down a bit.
     
  5. Tim McNamara

    Tim McNamara Guest

    Dan Daniel <[email protected]> writes:

    > On Sun, 22 Feb 2004 17:59:30 -0600, A Muzi <[email protected]> wrote:
    >
    >>> Dan Daniel writes:
    >>
    >>>>I built up a new rim with a pinned joint (Sun Assault, pre-welded version) and there is a slight
    >>>>offset at the joint on one side. Of course I built the wheel up so that the higher point in on
    >>>>the back side of the joint, not the front, so I have a definite 'tick' when I apply the front
    >>>>brake. I can both hear it and feel it. Is there a clean way to get rid of this bump, or is it
    >>>>best to just sit back and let the brake pads wear it down?

    Have you tried just turning the wheel around so that the high side goes in the other direction?
     
  6. A Muzi

    A Muzi Guest

    > On Sun, 22 Feb 2004 17:59:30 -0600, A Muzi <[email protected]>
    > wrote:
    >>*But not so tightly as to change the rim's shape!

    Dan Daniel wrote:
    > Wait a minute- that's exactly what I *do* want- a new shape! :)

    In my asterisked comment I meant take care to avoid inadvertently crushing the side that's in
    the vise jaw.

    --
    Andrew Muzi www.yellowjersey.org Open every day since 1 April, 1971
     
  7. Dan Daniel

    Dan Daniel Guest

    On Sun, 22 Feb 2004 20:31:50 -0600, Tim McNamara
    <[email protected]> wrote:

    >
    >Have you tried just turning the wheel around so that the high side goes in the other direction?

    So now my next question- does the orientation of the 'pull' spokes matter on a front wheel?
     
  8. Jobst Brandt

    Jobst Brandt Guest

    Dan Daniel writes:

    >> Have you tried just turning the wheel around so that the high side goes in the other direction?

    > So now my next question- does the orientation of the 'pull' spokes matter on a front wheel?

    No, and it doesn't matter on the rear wheel either.

    Jobst Brandt [email protected]
     
  9. Tom Sherman

    Tom Sherman Guest

  10. Tim McNamara

    Tim McNamara Guest

    Dan Daniel <[email protected]> writes:

    > On Sun, 22 Feb 2004 20:31:50 -0600, Tim McNamara <[email protected]> wrote:
    >
    >
    >>
    >>Have you tried just turning the wheel around so that the high side goes in the other direction?
    >
    > So now my next question- does the orientation of the 'pull' spokes matter on a front wheel?

    No. Try this first as it's the simplest and easiest fix, taking only a few seconds. You may need to
    re-mount the magnet for your computer.
     
  11. Dan Daniel

    Dan Daniel Guest

    On Mon, 23 Feb 2004 21:25:19 -0600, Tim McNamara
    <[email protected]> wrote:

    >Dan Daniel <[email protected]> writes:
    >
    >> On Sun, 22 Feb 2004 20:31:50 -0600, Tim McNamara <[email protected]> wrote:
    >>
    >>
    >>>
    >>>Have you tried just turning the wheel around so that the high side goes in the other direction?
    >>
    >> So now my next question- does the orientation of the 'pull' spokes matter on a front wheel?
    >
    >No. Try this first as it's the simplest and easiest fix, taking only a few seconds. You may need to
    >re-mount the magnet for your computer.

    Hmmm... I'll have to get a computer first!

    Thanks for the suggestion. Done, and the small 'tick' is much less.
     
  12. Dan Daniel

    Dan Daniel Guest

    On Mon, 23 Feb 2004 20:56:36 -0600, Tom Sherman
    <[email protected]> wrote:

    >Dan Daniel wrote:
    >
    >> So now my next question- does the orientation of the 'pull' spokes matter on a front wheel?
    >
    >Yes. ;) <http://www.sheldonbrown.com/power_wheel.html>.
    >
    >Tom Sherman - Quad Cities (Illinois Side)

    Alright, my next wheel will be ALL pull spokes! Now the *really* important question- do the spoke
    heads go to the inside or outside? I assume the inside would be more aerodynamic, although I will
    probably have to smooth down the spoke heads on the outside of the flange to lessen the
    turbulence...
     
  13. Dan Daniel

    Dan Daniel Guest

    On Mon, 23 Feb 2004 20:11:44 GMT, [email protected]
    wrote:

    >Dan Daniel writes:
    >
    >>> Have you tried just turning the wheel around so that the high side goes in the other direction?
    >
    >> So now my next question- does the orientation of the 'pull' spokes matter on a front wheel?
    >
    >No, and it doesn't matter on the rear wheel either.
    >
    >Jobst Brandt [email protected]

    Ok, thanks. Curious- is this in your book? About time I got a copy, so 'yes' or 'no' is all I ask.
     
  14. Tim McNamara

    Tim McNamara Guest

    Dan Daniel <[email protected]> writes:

    > Alright, my next wheel will be ALL pull spokes! Now the *really* important question- do the spoke
    > heads go to the inside or outside? I assume the inside would be more aerodynamic, although I will
    > probably have to smooth down the spoke heads on the outside of the flange to lessen the
    > turbulence...

    You're kidding, I hope...
     
  15. Dan Daniel

    Dan Daniel Guest

    On Mon, 23 Feb 2004 22:58:27 -0600, Tim McNamara
    <[email protected]> wrote:

    >Dan Daniel <[email protected]> writes:
    >
    >> Alright, my next wheel will be ALL pull spokes! Now the *really* important question- do the spoke
    >> heads go to the inside or outside? I assume the inside would be more aerodynamic, although I will
    >> probably have to smooth down the spoke heads on the outside of the flange to lessen the
    >> turbulence...
    >
    >You're kidding, I hope...

    What really scares *me* is that there are probably people who do just this sort of thing...

    (Yes, I'm kidding.)
     
  16. Tim McNamara

    Tim McNamara Guest

    Dan Daniel <[email protected]> writes:

    > On Mon, 23 Feb 2004 22:58:27 -0600, Tim McNamara <[email protected]> wrote:
    >
    >>Dan Daniel <[email protected]> writes:
    >>
    >>> Alright, my next wheel will be ALL pull spokes! Now the *really* important question- do the
    >>> spoke heads go to the inside or outside? I assume the inside would be more aerodynamic, although
    >>> I will probably have to smooth down the spoke heads on the outside of the flange to lessen the
    >>> turbulence...
    >>
    >>You're kidding, I hope...
    >
    > What really scares *me* is that there are probably people who do just this sort of thing...

    Keep reading rec.bikes.tech. You'll meet some of them.
     
  17. A Muzi

    A Muzi Guest

    > On Sun, 22 Feb 2004 20:31:50 -0600, Tim McNamara
    > <[email protected]> wrote:
    >>Have you tried just turning the wheel around so that the high side goes in the other direction?

    Dan Daniel wrote:
    > So now my next question- does the orientation of the 'pull' spokes matter on a front wheel?

    No. And some show-off wheelbuilders (me) build fronts such that the wheel is the same dropped in the
    bike either way. (Viewed from each side, outside spokes go the same direction) Which also doesn't
    matter at all.

    Another short question - what "pulls" on a front wheel?

    --
    Andrew Muzi www.yellowjersey.org Open every day since 1 April, 1971
     
  18. A Muzi <[email protected]> wrote:
    >Another short question - what "pulls" on a front wheel?

    A hub dynamo or disc brake causes hub-rim torque, so there are pulling front spokes on bikes with
    these fitted.
    --
    David Damerell <[email protected]> Kill the tomato!
     
Loading...
Loading...