Nitrogen in Tires?

Don't worry..... if there's a fire that impinges the tire, it's gonna burst no matter what's in it. I can only describe the event as "exciting".

Duals can be really neat as the concussion from the first event can trigger the second event.

Well this isn't really true, if I understand what you are saying. Nitrogen is close to an ideal gas at atmospheric temperatures and pressures, so PV=nRT. For a given cylinder V is a constant. n is a constant unless you add gas. R is a constant over the sort of temperatures and pressure most people will encounter. so P1/T1 = nR/V = P2/T2 which implies P2=P1*T2/T1. Which means the pressure increases linearly with increasing temperature. This does not mean "a given cylinder size will have very close to the same psig reading when cold as it will when hot." It does mean the change in pressure as temperature increases will be consistent and predictable.

Ed

However, plotting the linear change of P vs. T may reveal the slope of the line for dry nitrogen is much, much less than the one for humid air.

I work for the company that makes the nitrogen generators, Ingersoll-Rand Corporation. Here are the benefits, in a nutshell---

2- Nitrogen expands/contracts less due to changes in temperature-hence, less worry about proper inflation

About the purity of the nitrogen in the tire, even an uninflated tire on the wheel contains "air"---in order to reach the proper nitrogen purity (95+%), the tire must be purged at least twice, the more purgings, the higher the resulting percentage of nitrogen. Purging is accomplished by filling the tire with nitrogen, then bleeding the pressure back down, refilling, etc.

Somehow, for all practical purposes this whole concept seems to me to be a tempest in a teapot.

Given that air is approximately 80 parts nitrogen and 20 parts oxygen and the oxygen seeps out faster than the nitrogen, then every time that you lose enough of the mixture the ratio changes to favor the nitrogen. That is, you might have 75 parts of N and 10 parts of O. Then you pump in the same

Now two last thoughts. If you are concerned about a race car that fills the tire once and then drives the tire to destruction refilling is not going to enter into the equation.

Secondly, don't bother to pick my little analysis apart. I know it is a grossly simplified discussion. I am merely trying to illustrate a point that says, for my money, air in tires has a long and proven history and gilding the lily is OK if that is what you want to do, but consider what happens in real life anyhow. I have 40K miles rated tires and they get a little air lots of time during their lifetimes.

Charlie

I'm of the opinion that nitrogen in street car tires is pretty much marketing hype. We always use nitrogen in our race car tires because it's completely free of water vapor, resulting in consistent pressure changes when heated.

I'm also not buying the arguement of oxygen migrating through the tire quicker since oxygen is a larger molecule than nitrogen. Anyone who SCUBA dives with trimix (O, N, He) knows that your dissolved gas uptake is quicker with helium than with nitrogen because it's a considerably smaller molecule, second only to hydrogen. I'd imagine it's the same for O2 vs. N2.

Works for me...... for dry-chem extinguishers, there are 3 choices for propellant...... CO2, nitrogen and "air". Most expensive and most preferred is nitrogen..... due to the thermal stability. CO2 loses in cold weather and air is near unpredictable.

After all these years, I have had little trouble using 'air' in my daily driver tires for something like near 40 years. I fail to see why this would become an issue now.... except, of course, if the interested parties prefer latties (sp) over black coffee or are afflicted with other neo-yuppie tendencies. If some wierdo wants to put nearly a C-note of something in their tires, more power to them. If you tell me that at a social gathering, you will see beer come out my nose (I WILL laugh that hard).

While professional races are won or lost because of details (we are takling more than the lifetime earnings of most on the NG - per race), I can understand getting anal...... For the eight o'clock 500, I think we can reax a little.

Well, I'm not sure what the real cost of nitrogen filled tires is, but I noticed while gassing up at Costco today that they now have a banner up that says they fill new tire purchases with nitrogen... *shrug* Must not be too spensive if Costco offers it.

I haven't dug deeper to see if they charge more for it or if it's standard fare with a rubber purchase. The banner implied that there wasn't a charge..

Ingersoll-Rand

(MMccoy01) I think NASCAR uses nitrogen in their air impact wrenches that they put the wheels on the car with. Not in the tires. You would be wrong. 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 ==================== they just did a special on the history channel about impact wrench technology. started out in 1936 when the wrench was first designed to loosen up rusted nuts on the old locomotives.

back in the days of racing cars, the best a good tire changer with a

and for what's worth, that is also where the technology came from for the 60/40 impact wrench came from. the tires heated up the lug nuts and they increase their tension holding the tire on. when the car came into the pit stop, they set the impact wrench for 60% to remove the tire, but set it to 40% to torque the tire back on because they don't need to extra torque to tighten the lugs.

hope this help clears up some of the issues.

as to why do they use nitrogen in tires? i'll answer that question with a question. who would ever think they would get someone to pay for bottled drinking water when you can get the same water out of the drinking tap?

~ curtis

knowledge is power - growing old is mandatory - growing wise is optional "Many more men die with prostate cancer than of it. Growing old is invariably fatal. Prostate cancer is only sometimes so."

There is probably some truth to that in regard to auto tires but the folks who operate fleets of big rigs and who use retreads find that the use of nitrogen has sufficient benefits to be worth the added cost.

-- 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

I came across this article on the subject: