What will happen if nitrogen is filled in car tyres instead of air?
Shouldn’t be any different. 75% of air is nitrogen in any case. As the first answer suggested, people do desire to use nitrogen because of larger molecules and hence potentially less leakage. But think about it and assume it was true. If I fill the tyre with air then in a little while, the smaller molecules would have leaked out leaving the larger molecules in a much higher percentage. Let us say now nitrogen is up to almost 100% of the remaining air. Then I fill the tyre again to bring it up to normal pressure. So now nitrogen will be the original 75% plus 75 % of the remaining 25% that I just filled. This comes out to be almost 94%. The next round will take it to 98% nitrogen. So why would I want to fill with nitrogen for such a reason when filling with ordinary air will bring me up to the same result after a few fillings? I think it is just a gimmic.
