ktmrfs wrote:
PartyOf Five wrote:
Our mechanic suggested nitrogen in the car tires if we did a rotation as winter approached. Apparentky it doesn't contract and expand as much in the cold and so is better in extreme temps.
That was already a few years ago- the fad seems to have died down.
NOT true. all gases follow boyles law PV=RT. since V (volume) is constant, P is strictly a function of T (temperature) where T is absolute temp, E.G. room temp is 273 or so Kelvin
Nitrogen molecules are slightly larger than Oxygen, so pressure drop from migration through the tire will be very slightly less.
Personally I think the less change in pressure is caused by the dryer nitrogen compared to regular air. There should be no water vapor in the nitrogen fill, and water vapor will expand and contract more than gases without the water vapor. JMO anyway.
But basically unnecessary, just a way for some place to make a few extra pence.