Nitrogen versus air: modest physics, oversold promises
Nitrogen inflation has real but small advantages. Nitrogen molecules permeate rubber more slowly than oxygen, so a nitrogen-filled tyre loses pressure somewhat more slowly over the weeks, and the dry gas carries no water vapour, which means slightly more stable pressures as temperatures swing and less internal corrosion of steel belts and TPMS valve hardware. In a country where the gap between a January dawn and an August afternoon can be 35 degrees, more stable pressure is a genuine, if modest, benefit. Airlines and racing teams use nitrogen for these reasons at extremes far beyond road driving.
One caution: mixed fills are harmless but pointless. Topping up a nitrogen fill with ordinary air at a petrol station does no damage whatsoever, and the widespread belief that it does keeps drivers running underinflated while they hunt for a nitrogen point. Correct pressure with plain air always beats low pressure while waiting for the right gas.