I've been using about 79% nitrogen in my tires for years. So far so good.

 

Like we said it's not the mix of the gasses that cause that problem, it's the water changing back and forth from vapor to liquid.

From my high school chemistry:

combined gas lawn (applies to pretty much all gasses and mixtures):
(P1*V1)/T1=(P2*V2)/T2

Which means that once you increase temperature you will get an increase in pressure, volume or a combination of the two. Unless you use a liquid to fill your tires you can't get away from the pressure going up as the temperature goes up. You could even work the exact numbers if you knew the size of the empty space in your tires. Someone give me the dimensions of a tire - cross section size, rim diameter and total tire diameter - and I'll figure something out.

Calvin

 

We use calcium in our John Deere 9400/9500 front tires on our tractor pans- adds weight in the tires instead of hanging plates on the front, which have fallen off on occasion

 

Huh, I guess I didn't realize that's what you were saying. I thought you were saying both oxygen, or air from a service shop, and nitrogen would increase in pressure and be at the same temperature in the same given situation (the same tire, with the same number of miles and ambient air temperature).

 

Want a dry gas to inflate your tires? Come to Arizona - 9% relative humidity this afternoon.

 

For normal cars for normal daily road use air is fine. As others mentioned, it is making sure whomever pops the bead and initially fills the tire uses a dry air (ask them to bleed their compressor). Of course you could just evacuate out as much air as possible on your existing tires and refill using your own compressor, then do it once more just in case.

For those truly retentive and racers, a recent interesting outcome from the Ferrari Formula 1 'spygate' reveals their tire air formulation and why:

It has been widely reported that the gas used by Ferrari was carbon dioxide and, whilst this is partially correct, it’s not the whole story.
Contrary to those that refused to believe alternate tire gasses could have a genuine impact on performance, Ferrari indeed developed an innovative solution. (For a revealing of all of the test results, purchase the December issue of Racecar Engineering.)

In fact, the gas used by Ferrari is a hydrofluorocarbon (HFC)-based mixture designed specifically for use in racecar tyres, though not dissimilar in composition to gasses used in refrigerators, which are comprised entirely of hydrogen, carbon and fluorine.

A team headed by Andrea Seghezzi of Monza, Italy, in association with Gruppo Sapio developed the gas and subjected it to extensive track testing.

It was discovered that the HFCs were able to effectively conduct the heat generated during the rotation of the tyre to the wheel rim at a more or less constant pressure. The wheel rim then acts as a radiator, exchanging the heat with the outside air, maintaining a lower internal temperature and preventing it from overheating. This is particularly effective on aluminium or magnesium wheels.

Racing rubber inflated with air also suffers from the effects of some internal chemical interactions, which damage the structure of the tyre, and can result in a sudden drop in performance. Due to the high capacity for heat transfer, tyres inflated with the new gas mixture achieve excellent longevity, since the temperature of the tyre is kept low and the pressure is constant.

After extensive tyre testing the best blend of HFCs was found to be 52 per cent Tetrafluoroethane, 44 per cent Pentafluoroethane and four per cent Trifluoroethane. This mixture, known as HFC R404 A, was found to be most effective in a racing tyre when it was inflated with a blend of 50 per cent HFC R404 A and 50 per cent CO2. The use of refrigerant gas to cool the tires and radiate heat away from the carcass through the wheel is but one of many secrets McLaren was privy to.

The use of this new gas mix for tyres has implications far beyond Formula 1, of course, as using it allows teams to run softer compounds for longer, or to work the tyres harder.

It could also be that there will be worthwhile benefits in races run over longer distances, like NASCAR or Le Mans.

The court case continued without revealing the precise details of HFC R404 A, but it transpires that, despite the encouragement of the drivers, a Bridgestone engineer doubted whether the gas mixture would be effective if used on the McLaren MP4/22. However, it is thought that the McLaren drivers were not fully aware of the gas mix, rather they only knew of the CO2 element.

 

I have to tell you, if you filled your tires with liquid and left no gas space at all you'd see pressure peaks that I think would blow the tire apart, or at least off the wheel. Liquids do expand when heated and if confined within a closed volume pressure climbs. If you want to see it happen give this a try. You could use a 6X1/2 pipe nipple, 1/2" cap, 1/2X1/4 bell reducer and a standard 1/4" threaded gage. First cap one end of the nipple and put the bell reducer on the other end. Now fill it up with any liquid you want and install the gage in the bell reducer on the other end and leave it out in the sun. For more dramatic results paint it black first...

I work in a power plant and when we light off a boiler we have to drain water to maintain level within range of indication on the sight glass. This is with a vent open to bleed some of the wet steam and condensate from the header as it heats up. Pressure goes up, level goes up, temps go up, and it's all due to adding heat. The expansion ratio of water from liquid to gas is something astronomical like 10,000:1. I'm not sure of the exact ratio but it's really high, you can look it up if you want. That's why the moisture in the air causes a greater pressure change. Of course, the pressure the water is under will effect the temp at which this phase change occurs.

 

I wonder why they use nitrogen in shocks? Corrosion? I think not....more for a constant pressure level during the sever use of the shock on off road courses. It makes tuning a shock more of a consistence process.

 

At a local tire shop they want $37 dollars to refil your tires with nitrogen.LOL.I get a great laugh everytime I hear the ad on the radio.What'll they think of next bottled water.Lol imagine that now that'll be funny

 

Nitrogen is a inert gas hot or cold the gas dosen't expand ar contract.

 

Where are you getting your data from?

 

The pressures that you are talking about is the temp that water boils and changes to a gas at different pressures. At sea level (14.7 PSI) its 212 degrees, at 35 PSI its 259, at 60 PSI its 293, and at 80 PSI its 312. I didn't look at 120 PSI which is what a lot of compressors are set at but would guess it would be up around 400. It the air sets in the pressure tank any amount of time most of it will change back to water, that is why you have a drain valve on msot tanks. So the % of moisture in the air they add to the tire is much lower than the % in the outside air. Most shops should also have a drier after the tank to reduce the moisture even more so for the most part it should be dry air that is going into the tire if it was checked in a lab. Any oil from the compressor should also be trapped and drained from from the compressor. The drier the air the less change it will see in pressure due to a temp change.

 

Wanna bet?

 

a bit of info..

http://en.wikipedia.org/wiki/Nitrogen

http://www.uigi.com/nitrogen.html

 

Obviously you've never studied physics.