please note, nitrogen is used in air plane tyres and F1 cars because it is not affected by temperature. as such the plane tyres don't suffer at altitude where its cold and F1 tyres don't change profile under the extreme temperatures that they get too. your car tyre will never get to those extremes. as far as air is concerned, it is already 78% nitrogen, its just not worth the extra money. as for moisture, most if not all moister is removed by coalescent filters in air compressor systems and the rest is taken by the heat of the compressor when in use. in my opinion the extra charge for inflating your ordinary car tyre with nitrogen is not worth the extra cash. I am a veteran of 30 yrs in the industrial gases business.