Re: [Phys-l] zeroth order and first order

[Rick Tarara <rtarara@saintmarys.edu>]

----- Original Message ----- 
From: "John Denker" <jsd@av8n.com>
> I bicycle tires there's no glue, and in car tires the "glue"
> is not strong enough to do this job.  It's that super-strong
> wire in the bead that does the job, due to its tension *and*
> curvature.

Well on some bicycle tires there IS glue (light weight bikes/wheels with 
glue-on tires) but the glue is to keep the tires from slipping radially on 
the wheels--or off the rims altogether.  [When such fails the whole tire can 
come off the rim--jam in the brakes--and you get a good example of Newton's 
first law with the rider--me!]

I'm thinking that bicycles may not be a really good analogy to car tires in 
that the inflated tires serve different purposes.  Am I wrong to believe 
that one CAN ride a bike on the tireless rims?  If so, the tires basically 
soften the ride (they may stiffen the rim as well through compression?)

The analogy as I understand it is that the spokes are like the 
sidewalls--leaving only the tread to be like the bike tire (or is it just 
the wheel rim?)  The tension in the sidewalls is due to the inflation 
whereas the inflation of the bike tire doesn't effect the spoke tension.
Is all that correct?

Rick