"Keith Alexander®" <keith@REMOVE!nootrope.net> wrote in message
news:
[email protected]...
> On Fri, 10 Sep 2004 23:07:56 -0500, "Carl Sundquist"
> <[email protected]> wrote:
>
> >How old are the spokes?
>
> *** Bike was purchased on 8/1/04.
> 450+ miles on it.
Old age fatigue not a factor then.
> >How much tension is on the spokes?
>
> *** How can I measure that?
It's not easy if you are inexperienced. There are tensiometers available,
but recognizing spokes tension great enough to pop spokes should be apparent
to anyone with a little wheelbuilding experience.
> >Where on the spoke did it break?
>
> *** Popped out at the nipple.
> Still attached to the hub.
Hmmm ...
> >Was it a pulling or non pulling (torque-wise) spoke?
>
> *** How can I determine that?
Pulling spokes are the ones which "pull" the rim around. IOW, in a rear
wheel with crossed spokes (as opposed to a wheel where the spokes radiate
out directly to the rim and do not cross each other) the pulling spokes will
be the ones going counter-clockwise from the hub on the drive (cassette)
side and clockwise from the hub on the nondrive side. Pulling spokes tend to
fail because of stresses due to wheel torque.
> >Drive side or non drive side?
>
> *** Drive.
>
> If by "drive" you mean the side with the cassette.
Correct. Drive side spokes are subject to more tension than non drive side
spokes dur to hub flange offset to fit the cassette.
Hmmm. As a general rule, old, pulling, overtensioned drive side spokes are
the most likely to fail, but they do so more commonly at the head (hub).
Your wheels were most likely machine built, so theoretically should be
tensioned reasonably correctly. Who repaired the initial spoke break? How
many broken spokes total? All of the same type (side of the hub,
pulling/nonpulling)? I assume they were all on the rear wheel. How much do
you weigh and how many spokes were in the wheel (I expect 32 spokes for a
production wheel)?
