My first wife blew a Raleigh Shopper rear tyre off the rim. A long descent where she rode the rear brake all the way down, a bumpy unmade road and the BOOM! sounded like a cannon going off. The tube was in shreds and the sidewall split. I went to help and promptly burnt my fingers on the steel rim. I'd estimate the rim to be well over 150C.
On a similar topic the airline demands that tyres be deflated is a load of fetid dingo kidneys. Give sea level pressure is 14psi, at altitude it is less, but even a vacuum it will only add 14psi to the pressure! Take into account that at high altitude the temperature can be -40C and only a modest reduction below the maximum sidewall pressure should be fine.