Most of the better quality (EXPENSIVE) tires s hould have DRY air pressure. Therefore, like aircraft tires, nitrogen should be the dryest air in any cylinder.
So, No2 is preferred to keep tires fron rotting from the inside out. I always let some air out of 'dem "quarter" machines until the water quits squiring all over my fingernails. Then I put the rest of my 25 cents worth in the tires of my road equipment.
Nitrogen is mandatory in high flyer-type airplanes so the tires do NOT go FLAT while in the wheel wells. Constant pressures at COLD altitudes. 100 miles high.
John,PA So NITROGEN CHARGED should mean "dry gas".......I assume.