Shrek wrote:i read somewhere that Ferrari put 52% Tetrafluoroethane, 44% Pentafluoroethane and 4 % Trifluoroethane in the tire, don't know if it is really true though.
That was in the early 2000s, I believe. After that they wrote a rule asking for common gasses to crank down on that.
As for the expansion of "moisture" I see no reason why it would be much different from that of Nitrogen and Oxygen (as long as it does not condensate). Chemically it can store energy internally in a different way, but the effects should be quite negligible, with ideal gas behavior being a good enough approximation for most purposes.
As for Magnesium, and even Aluminum, they are reasonably inert when solid because the surface is already oxidized, but the elemental (non oxidized) material underneath is quite flammable. Both Magnesium and Aluminum powder will actually self-ignite when exposed to air simply if they are ground finely enough and devoid of the protective oxide layer.
So touching the wall, by grinding the wheel rim a bit, is more than enough to create flames and sparks of Magnesium and Aluminum, that will self ignite and then also burn any rubber or paint they managed to scrape along.
Rivals, not enemies.