Frank Krygowski said:...
The car was parked in the sun (don't recall the outside temperature).
When I finished work and drove to the friend's house, I pulled out a
bike with a blown back tire. Obviously, that tire'd blown off the rim
while the car was parked.
Air pressure would have been between 100 psi and 105 psi that morning.
Of course, I don't know the eventual air temperature inside the car. As
a guess, I'd assume the rear tire was partly in the sun as it came
through the rear window. I don't know if it was that part of the tire
that slipped off the rim, though.
What strikes me about this is: there was certainly a rise in
temperature, but I'm sure the rim didn't get anywhere near the boiling
point of water, let alone 500+ degrees. And there was no braking force
which might tend to cause any further shifting, creeping, etc. of the
tire on the rim. All that could have done it would be the (as we've
seen) moderate rise in air pressure, and the possible effects of
temperature on the rubber and other materials.
Further memory on that event: I just remembered that the tire was
ruined. As I recall, the bead wire was ripped away from the sidewall
for a few inches of circumference.
I know that typical blowoffs don't rip the tire this way. Still, I
wonder if this gives further evidence that the problem is related to the
effect of temperature on the materials. I think most of us agree it's
not simply high pressure doing the damage.
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Frank Krygowski [To reply, remove rodent and vegetable dot com,
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