Nitrogen in lieu of compressed CO2

Yes.

Aeroplane tyres are filled with nitrogen.

Yes.

The are supposed to run cooler with less wear.

One disadvantage is when you need some air in a small town.

Yes. In some places you have to settle for N85 from the compressor. It's an archaic formulation which is only 85% Nitrogen. The balance is various adulterants.

Of course it will (normal compressed air is mostly nitrogen anyway) any stable, noncorrosive gas that stays a gas at the expected pressures will work. A few local tyre merchants sell nitrogen to the "petrol heads", but I've never heard a convincing reason to use it. The main advantage seems to be that it's dry and comes in easy to carry gas bottles.

Does anyone have any rational reason for its use? Jeff

The answer to the question is, Yes. One reason is reported to be that there is a smaller pressure change with temperature when using nitrogen as opposed to air. This is the reason many racing teams use nitrogen. The other (and more important in my view) reason is that we have entered a world of run-flat tires. These tires require pressure sensors in the valve stems to inform the driver when the air pressure in the tire is too low. If there is excessive moisture in the fill gas, it will condense on the pressure sensor in cool weather, causing damage to the sensor. Any dry gas will do, but nitrogen is cheap. You don't want to use a gas with small molecules like helium or hydrogen because the the molecules dffuse through the rubber tire too quickly.

Oh yes, there was this weeks long thread in some Citroen forum about the merits of nitrogen in tyres compared with ordinary air. Lotta otherwise sensible posters claimed considerable improvements in roadholding and comfort. As air is mainly 80 % nitrogen and 20 % oxygen, which has very similar thermodynamic behaviour at the conditions in question, it is most unlikely that the spring characteristics of a tyre change much. Maybe diffusion through butyl rubber is a bit lower for nitrogen, so the pressure might be kept better. And corrosion might be reduced in cases of very humid atmospheric air. - But compressed carbon dioxide (see title)? Is this really an option? Must be a mistake.

What is the economical benefit of using nitrogen instead of air for inflating tires? Isn't nitrogen more expensive than air? The nitrogen content in air is already 78%, does it technically really make a big difference?

The technical difference is that it doesn't contain much water vapour in comparison to air. At +10km there is little propspect of the inside of the tyre freezing up, which may be an important consideration when the tyre is called upon to support an aeroplane suddenly as it lands. If it is, then an economic difference can then be imagined...

Nitrogen for our tires is smarter for many reason; The Aviation use it, racing cars use it , turning a curve at 250MPH you have to sure , it prevent BLOWOUT ,, Double the tire lifespan and a tire that maintain the right air pressure will reduce is energy bill by 3 to 5%.

As NITROGEN is an inert gas it does not change pressure at different air atmosphere a plane et 35,000 feeth up , the wheather is MINUS 55 and at landing +100 and 130 degree.

Mr Boeing and figther pilot rely on it.

Whoa here, can't let this go by. First Nitrogen is NOT an inert element. NOx, trinitrotoluene etc. I asked a similar question in another post and still am not convinced it makes any sense. Previous posts referring to moisture as the problem, I have to say that the moisture content of a gas (humidity) has nothing to do with the gas itself. Also,the molecular weights of air vs. nitrogen are too close to have any large density variations.

I agree that any oxidation that occurs with the tire would be eliminated but that reaction would normally take years to destroy a tire. I still have not heard a scientific explanation

K, gotta jump in on this one. I actually worked for a tire store for a while and not only is nitrogen safe to use in tires, some places actually do use nitrogen to fill tires. Not entirely sure why, but nitrogen does not experience as much thermal expansion as compressed air. You can tell if your tires have been filled with nitrogen because most places will use a green valve stem cap.