On Tue, 9 Sep 2003 16:47:07 +0100, "Just zis Guy, you know?"
wrote:

"Tim McNamara" wrote in message
...

A bicycle wheel does not support a
load by elongation of the spokes- exactly the opposite, in fact. The
wheel "stands" on the spokes between the hub and the ground, rather
than hanging from the top of the rim as your model would require.

Whoop! Whoop! Flamewar Alert!

Having reviewed a finite element analysis of a bicycle wheel under load,
what happens is that the bottom of the rim deflects, reducing the tension in
the bottom spokes,

So the spokes are compressed.

but to describe this as "standing" on the bottom spokes
is misleading because if their tension ever below zero during the load cycle
the wheel becomes unstable and rapidly fails.

It is possible to compress something that is in a net state of tension
(and stays thusly).

It is true to say that the spokes undergo most of the cyclic change in
tension in the bottom few tens of degrees of arc.

But to describe it as standing on the bottom spokes is like saying you can
stand on a piece of string provided it's kept under tension by some other
structure.

I'll bet most people don't know or understand that either.

--
Chris Bird