Quote: I do not change the air in my tires till there is a leak.

Has anyone any experience with nitrogen in their Barth tires???
...have had some experience in allseason tires in Canada....

I use ~80% nitrogen (air).

quote:

Originally posted by Rusty:
I use ~80% nitrogen (air).

In theory Nitrogen is great as it lacks the water content that would be in just compressed air but the reality is you get 80 percent from the air itself and tires are made pretty darn good these days anyways so long as you got a good tire guy putting them on and cleaning your rims if needed.

My story and I am sticking to it. Sometime in the mid-80s I was given a tour of the pits at Darlington. I noticed each pit was stocked with many compressed air tanks. I asked why they used these and why so many. The answer was they couldn't use a compressor so they used the bottles to drive tools. I mentioned that bottled nitrogen was a whole lot cheaper and wouldn't support combustion.
Memory is a fragile and ductile thing but it seems it was not long after this there was some advertising of nitrogen for tires. It is dry, and has a very slightly greater predictability of response to temperature than compressed air but it ain't worth spending money on in my estimation.
Tim

Interesting...

I have seen nitrogen touted as a superior tire gas. I would like to see actual tests of this...

As for inflation loss, we are talking about something called effusion, ie a gas migrating through a porous membrane. (Think of a balloon leaking)

Graham's Law of Effusion states that the relative rate of effusion of gases is inversely related to the square of the molecular weight of the gas. Ie, light gases like helium He(4 amu) will have a higher rate of effusion (loss) than heavier gases like N2 (28 amu) or O2 (32 amu) Think balloons again.

Air is a mixture of gases, mostly N2 (78%), O2 (21%) and Argon (1%) Since nitrogen is lighter than oxygen, Graham's Law predicts that nitrogen should leak (effuse) FASTER than pure oxygen, and air, being mostly nitogen, should leak down faster as well.

OTOH, nitrogen is unreactive at tire temperatures. This is good 2 ways. If any tire gas reacts and combines with subtances in the tire, the gas is lost. Even though the tire has not leaked the gas pressure will be less.

Nitrogen will not react inside the tire and is not lost this way. (Also, unrelated here, many tire men have been injured by explosions whe dismounting tires that have been inflated with the "fix a flat" aerosol. Many use propane for the propellant gas. Being flammable it can ignite and explode with any oxygen in the tire. Nitrogen eliminates this problem)

Oxygen, being more reactive could conceivably combine with tire compounds and be lost from the tire's gas. Not sure if this does occur much at tire temperatures...

OTOH, if you have ever let the "air" out of a tire you know it doesn't smell like air, something more in there now. Where do these oderant gases come from and what is their effect on tire gas pressure?

Bottom line, I can't build a clear argument why dry nitrogen should be much better than dry air, leak less, etc.

I have never seen lab testing for this.

Steve, I think the tire air smells like the tire did in the store when newish. The molecular size of N2 is larger than O2 because O has a greater charge. That said this comparison is way below that of splitting hairs by several factors of 100 of angstroms
I'm sticking with good old pretty dry air out of the compressor.
Tim

I agree. The few tests I have seen showed very small differences in leakdown rates, less than 2%. Dry air is fine.

A good discussion here: http://www.getnitrogen.org/pdf/graham.pdf

But once again, there is an argument for why O2 leaks faster, but no info on the actual difference measured in real tires...

So, if my tires lose 3 psi with air and only 1 psi with nitrogen the leak rate is "3 times faster" with air but still minimal.

I had to see for myself if Nitrogen could improve Handling of my BaRTH. Maybe the roads I traveled on when going to Michigan were better. Did the nitrogen help? Sellers of Nitrogen say it has less moisture. They also say that nitrogen "gives" less. I am not sure with only one trip on Nitrogen filled front tires what results are yet. The rut tracking seemed to improve, or maybe I am getting to be a better driver of the antique Barth?

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Has anyone else tried nitrogen in any vehicles they drive? Did the installer remove the air to a flat tire? Is it possible to pull a vacuum on at tire without unsealing the bead and entirely filling the tire with nitrogen?

There are two types of available Nitrogen, dry as used to purge A/C systems and water pumped, more readily available. Wonder what you've got in your tires?

I do not know. Comes out of a tank. Tall cylinder that says Nitrogen.

Good question for the Professor Steve, is nitrogen more or less compressible than air??? My thought is PSI is PSI tire expands if/when smacked!

Do not totally remember, but if it is dry nitrogen it would say so on the tank.

When I was in the round and round days we use nitrogen to air tires. Mostly because we didn't need a compressor or electric. Also could run impacts. The thinking the dry air would keep psi stable. I am not sure it made any difference. Just made us feel better. I know tire shops were filling with nitrogen and then putting green valve caps on. marketing ploy. The best you can do is check air pressure. I have not broke down for tire monitor system. My Regal had 1 installed from factory but sensors were removed when tires were replaced. Could not get info on it. Just has red indicator on dash. A good thumping bat is worth carrying.

I was able to get a picture of the nitrogen tank.

Tim's law states "Check pressure on Liz's Beemer tires regularly, check dash pressure reading on trucks tires regularly." Corollary: "Don't expect any need for action aside from season changes."
I think overall tire technology has advanced such that it is compatible with the set it and forget it generation. Afred E. Neuman, the driver of 21st century technology goals.