Come back Globalti - all is forgiven

[ColinJ]

So; if the tyres were in an unpressurised environment at 40,000 feet, would they explode?
If so, I will be deflating mine next week. If the plane I am on breaks apart at that height, I would hate to think that my bike tyres are going to be damaged.

If you think about it, the pressure in a tyre is (say) 100 psi. That is 100 psi greater than the ~14.7 psi atmospheric pressure acting on the outside of it. If you took the wheel into outer space so there was no atmospheric pressure, effectively it would be like putting 114.7 psi into the tyre in the presence of the atmosphere. I wouldn't be worried by adding 14.7 psi to any of my tyres! (It might make them uncomfortable to ride on, but they should not explode!)