Re: wheel puzzle
On Mon, 13 May 2002 17:37:52 -0500,
UniDak <UniDak.email@example.com> wrote:
> The answer is that it hangs primarily.
No, structurally it stands.
> Infact, I believe that it was
> Spinergy who came3 out with a type of flexable spoke.
Irrelevant - spokes are flexible. At least they’re fairly flexible,
and since they have pivoting connections at hub and at rim no bending can
be conducted to them, so they may as well be infinitely flexible (ie, bits
> There is no way
> the hub could stand with full pressure over it if a rim was laced only
> from the bottom half. Though it may stand longer if only laced from the
> top, it would still eventually turn to rubbish.
No, you can’t lace a wheel with spokes round only half the rim. Yopu
don’t actually get as far as doing anything with it - the rim would not
remain cuircular, the hub would not be central, and you wouldn’t have
anything useable as a wheel.
> There need to be all
> sorts of forces acting on the rim. Harper or someone could give you the
> technical parts, but my answer is that IT HANGS.
As I say up above, it stands. It stands on teh reduced tension in the
lower spokes. It has been demonstrated both with instrumented wheels
under test and with finite element analysis that teh tension in the lower
spokes reduces, while the tension in the side and upper spokes stays
pretty much the same as in an unladen wheel. This is why you should keep
your spokes tight - the wheel only works while the tension in the spokes
is greater than the maximum force you’re going to apply to the rim. If
you load the rim enough to make a spoke go slack then suddenly you’re
dependant upon the bending stiffness of the rim, and wheel failure is
normally not far away.
If anyone is still interested teh definitive text on teh subject is
probably “the Bicycle Wheel” by Jobst Brandt. It’s ISBN 0-9607236-4-1,
and is about 150 pages of book talking about nothing but bicycle wheels,
covering both the theory and the practicalities of building and
regards, Ian SMith
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