Re: [Phys-l] Another tire question

["Edmiston, Mike" <edmiston@bluffton.edu>]

Brian W. said...

> Sophisticated (in this context) means you can understand
> a pneumatic tire can be contrived with NO contribution
> from its upper half, and that this can be made to
> function on a spoked wheel assembly.

I guess I am not sophisticated because I cannot understand that unless
the tire is internally sectioned.

The spoked bicycle wheel/tire is no different than the auto wheel/tire.
The axle "hangs" from the top rim via the top spokes.  The rim "hangs"
from the top sidewall of the tire.

If you want much support from the bottom rim, that force can't come from
the bottom sidewall in an ordinary tire, because the bottom sidewall is
in tension, not compression.  However, if the tire would be internally
sectioned into cells spaced around its circumference, the air pressure
in the bottom cells could be more than the air pressure in the top
cells, and the bottom of the rim would be pushed upward by the increased
air pressure down there.

Michael D. Edmiston, Ph.D.
Professor of Chemistry and Physics
Bluffton University
Bluffton, OH 45817
(419)-358-3270
edmiston@bluffton.edu