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Re: [Phys-l] Another tire question

At 03:26 PM 11/10/2007, Rick T., you wrote:
Brian,

To me, what is still in question is just how is the force that acts upwards
ON THE WHEEL applied by the tire bead--which is the only part of the tire in
contact. I hope all agree that there is no force contribution ON THE WHEEL
from the air pressure.

...Supposing I am the Brian being addressed, I would concur that the tire
bead exerts considerable radially inwards and sideways (outwards) force on the rim when properly inflated, and it may be considered strongly attached by frictional force to the rim of the usual automobile wheel.

If the tire in question is of the type that can hold its pressurized
structure without a rim, this is the kind that bears upwards on the rim
in the lower half, where the upper half can almost show daylight under
if underinflated.

I am not disposed to think of the sidewall and bead as structural
entities.
The entity in question is an inflated tire which has distinct structural
properties when inflated. If you take one of Jiminy the Clown's long
slender rubber balloons, from the material of which toy giraffes are built, you will easily see that it can pass a compressive force
from one end t'other without changing shape, angles etc., etc.
Inflatable airplanes, of which there have been several prototypes
built also needed to handle both compressive and tensile forces via inflated fabric. Why should the inflated tire wall cause such
consternation?


Brian Whatcott Altus OK Eureka!