Nitrogen in Tires?

No, I saw it, too, at Costco. I think they do it for race cars, but I'm not relly sure why.

It's no dream. Here's something I posted on this in a different newsgroup. I got the info from a Tire Trade Mag.

-- Elbridge Gerry, of Massachusetts:

"What, sir, is the use of militia? It is to prevent the establishment of a standing army, the bane of liberty. . . Whenever Government means to invade the rights and liberties of the people, they always attempt to destroy the militia, in order to raise a standing army upon its ruins." -- Debate, U.S. House of Representatives, August 17, 1789

If they are doing it for free, it won't hurt anything. Your tires are already 80% filled with nitrogen today.

See

I only use AmsAir synthetic air in my tires.

It's 19.95 a tire to fill them, but I find that I get 50% better gas mileage, double the horsepower and a smoother ride. !

Sounds like you've been putting it in your cigarettes too.

Funny, this reminds me about a recent post in a bicycle newsgroup about riders' filling a leaking tires from their water bottles - first pour the water into their hand pumps. Water seems to hold fine with small leaks through which air would otherwise escape. No mention of nitrogen though.

Hey, maybe we could use nitrous oxide... pull over, let some out and have a party. Store it the spare Michelin LTX. Run on it if you need the spare, dispense it if you need to have some fun. :O) Hey, if water works, maybe it would make sense filling the spare with that if you're heading across the desert, for example. WOW. Think of all the possibilities .... spare antifreeze, spare champagne for when you pass 100K or go more than 1000 miles without having the replace something!

Hmmmmm ..... spare iodine in case we roll over :O)

Hey! How bout:

LF (Nitrous oxide) RF (Beer)

LR (Anti-freeze) RR (mecurichrome)

SPARE (urinal - Warning: Don't use Firestone tires in this position)

Just make sure you keep track if you rotate the tires :O)

I enjoyed that. "Nitrogen is used because it's inert"? Mentioning NASCAR/F1 racing, where the tire life is, at most, a few weeks total (from manufacture to junk), I seriously doubt that he difference between nitrogen and air is discernable as far as deterioration is concerned. On street tires, when's the last time we were presented with "tire deterioration due to using air instead of nitrogen" as a factor? Such tires are replaced long before it's a problem. On those that are owned by the LOL who keeps them for 15 years, ozone deterioration on the outside is more damaging than any on the inside from air. The points about more predictable pressure is well placed *in the context of racing*, but for street use, it's a non-factor, IMO. Yes, there's going to be less season to season differences in pressure with nitrogen, but those who don't check their tire pressure *at least* 4 times a year really aren't concerned about their own safety anyway, much less their passengers'.

IMO, it's another way to get money from those who think they know more than they do.

Bill Funk Change "g" to "a"

I think NASCAR uses nitrogen in their air impact wrenches that they put the wheels on the car with. Not in the tires. Mark McCoy McCoy's Market Bumpus Mills, Tennessee

You would be wrong. H

Yeah, I think you're right, but only partially. I looked it up and it seems they use nitrogen in their tires and also to power their impact wrenches.

Mark McCoy McCoy's Market Bumpus Mills, Tennessee

Actually they do use it in the tires as well as the tools. They did a bit about it during one of the races. Funny thing was, that Goodyear mounts the tires using regular "air" and then the teams let out the air and reinflate them with nitrogen. I'd love to see actual measurements that show there is a measurable difference.

Ed

IIRC from my high school chemistry, nitrogen expands less than air does with temp changes. I would think this would make a real difference in a Nascar race.

Bill Funk Change "g" to "a"

"Air" is mostly nitrogen (80%). 98% of what makes up "air" is close enough to an ideal gas so that the ideal gas law is a near perfect representation of the pressure, volume, temperature relationship. The ideal gas law is PV=nRT where n is the number of "moles" of the gas (think molecule count), P = pressure, V = volume, R is a gas constant, and T is temperature. In a closed system like a tire n and R are constants. V isn't a constant, but once the tire is inflated to near the correct pressure, you can treat it as one. So this implies, P1/T1=P2/T2, or P2=P1*T2/T1. This is a nice linear increase in pressure with an increase in temperature, which should be predictable. This is what the racers want. The one thing in air that causes problem is water vapor. It doesn't behave like an ideal gas at normal temperatures and pressures and the amount of water vapor in any particular sample of "air" can vary greatly over just a short pan of time or distance. The present of water vapor will cause non-linearities in the P vs T relationship and make the increase in pressure less predictable. I can't imagine it is greater than the errors due to other factors, but apparently professional racer think that it is. I'd love to see a study that could isolate the difference between regular air and pure nitrogen. And, I'd bet if you just used "dry" air the difference between that and pure nitrogen would be undetectable. But when you have millions to play with, you have to spend it somewhere, and pure nitrogen is readily available.

Ed

With them changing air pressure in tires in 1/2 pound increments to fine-tune the handling, I can see how nearly pure nitrogen could make enough of a difference in lap time consistency over 200+ miles to be worth it.

Jack

Perhaps there's also concern for what happens when tires burst if there's a fire?

And the final answer is "none of the above"...... The reason nitrogen is used has to do with it's volumetric stability - i.e. a given cylinder size will have very close to the same psig reading when cold as it will when hot. Racing teams aren't after tire longevity (not in the sense we are, at any rate) but are anal about consistency. If they want 14 psi in that right front tire, they have a better chance of maintaining that pressure using nitrogen than any other gas or mixture of gases.

HTH.

As far as street tires are concerned..... we should be a lot more concerned about what happens to the outside of our tires than what happens inside.

The thing is, how would you achieve a tire "full" of only nitrogen ?

I mean, just sealing the tire to the rim, it's already probably 80% full of air. It seems that if you were *really* concerned about it being filled with nitrogen you'd have to put the tire in a barometric chamber and evacuate all the air.. THEN refill with nitrogen. Otherwise you'd wind up with some mixture no matter what.