In article <casseres-211292131121@missmolly.apple.com>, casseres@apple.com (David Casseres) writes:
> In article <1992Dec15.150535.12805@waikato.ac.nz>, jrdodd@waikato.ac.nz
> wrote:
> >
> > It is true though that bike tyres that are pumped up hard then left in the hot
> > sun for a while will explode. On sunny afternoons after races I've often heard
> > the odd explosion as someone decides to tell the world how they didn't deflate
> > their tyres a bit after racing.
>
> I guess I forgot to mention in my previous post that in my desert riding I
> often leave the bike out in the hot noonday sun for an hour or more while I
> have lunch. The tires do not explode. They don't even fart. Neither do
> anyone else's. I am sure that tires have been known to explode, and
> occasionally while sitting in the hot sun, but I do not believe the hot sun
> is the cause.
>
> > While riding though, I don't think it's a problem. And I've known of trackies
> > getting their tyres 50psi over the prescribed limit when doing track work.
>
> But the tire probably gets even hotter while riding, so how does the theory
> work?
I too have seen (and heard!) a tire explode after a ride while resting at a
rest stop. It seemed strange to me at the time that the tire chose to explode
then and not while out on the asphalt, which gets very hot in Texas in the
summer time. I think the answer may be that while riding there is a signifi-
cant amount of convective cooling that removes heat from the tires. When at
rest, however, the tire is able to soak up solar heating without the cooling
benefit of riding. Furthermore, since the wheel is not turning, heating becomes
very localized. Perhaps the heat serves to weaken an already damaged portion ofthe tire, resulting in the explosion, rather than merely producing increased
pressure, which it seems a tire should be able to handle.
