Use a match & propane... no.. really...
I once saw video on Discovery channel about 4 wheelers in Iceland (of
all places) and it showed a really neat trick... when in the outback
(so to speak) and they need to re-seat a tire they fill it with
propane, (as best they can, obviously with it unseated some leaks out,
but they seem to get enough in) then they toss a match at it. It
literally explodes into a momentary fireball, but somehow the explosive
action is enough to seat the tire. I assume they come back and let
Propane out, and replace with air.. but the program was not a detailed
how-to, it just showed the video of them exploding the tire back onto
the rim. I am not nuts or desperate enough to try it, but it was some
pretty cool video...