Originally Posted by
TimEarl
Really? A flexing tyre (and an under-inflated one) will deform and increase rolling resistance,
that's why we pump them up so hard. Any extra, or stiffer sidewall material would add
to stiffness and decrease RR.
I said absolutely nothing about underinflating the tire. Pneumatic tires always deform to some degree to allow better grip and cushion the bike and rider from bumps. Otherwise we'd still be using solid rubber tires. Rolling resistance comes largely from the friction in the tire casing, yes, but making the sidewalls stiffer actually
adds to the frictional losses, because the tire has to fight itself to conform to the road surface.
With a tyre as small as a bicycle tyre, the deformation wouldn't be that great, so
you'd still get some braking, and with a flat, you wouldn't want to slam the brakes
full-on anyway. And given the choice between a flat tyre and a rim failure,
I know which one I'd choose. That's the point of the idea, moving the wear from
braking from an expensive, infrequently-replaced component to a less expensive
frequently-replaced one.
I can't tell if you're trolling or just haven't experienced a flat tire in a long time.