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Originally Posted by Pacedog
100% nitrogen? Air is already 78% so how does it factor in?
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The coefficient of expansion of nitrogen is less than that of oxygen so the pressure increase is less.
Its only significance is in racing where heat buildup is extreme (on the order of a hundred degrees or more) and critical to the tire not overpressurizing, losing valuable contact surface.
I've forgotten what the optimum tire temps for GY race tires but it seems that it was around 220 degrees F.
Using nitrogen on the street isn't much of a help in mpg where higher pressureis the item that increases mpg.
The single useaful thing about nitrogen is that bleedout of the pressure through the tirewall (what you thought they are impervious?) is slower with nitrogen because the nitrogen molecule is larger and harder to permeate through the rubber.