Nitrogen - $5 a tire

It's a scam. Air is 78% nitrogen and it's free.

This is the new thing at many tire places that are looking to distinguish themselves from other tire places and win your business. I believe Costco, for instance, uses Nitrogen.

If I remember my physical science lessons from HS many yeas ago, ordinary air is already comprised of about 78% Nitrogen. As such, even if you do not fill with pure Nitrogen, you are still filling with 78% Nitrogen!

I believe that the Nitrogen molecules are larger, so are less likely to leak through valve stems, rims, etc. This may also make it more immune to changes in temperature as well.

Bob

It's worth about 20 cents a tire.

Yes, you have been lied to. All gases very in pressure with temperature.

Matt

Absolutely untrue.

Nitrogen behaves exactly like air in terms of pressure/temperature expansion. Both are ideal gases and behave according to the ideal gas law at the conditions inside a tire. You probably learned that in high school, and forgot. Of course, the guy who lied to you probably did too. I'm surprised they'd be so quick to think up a lie (like the grinch)

On the seal, that's pretty stupid. You probably knew better. I tell you what seals better than air - water. Put water in your tires and you'll probably never have a flat. Just kidding, don't do that, except on the tractor.

The advantage of using nitrogen is that it's not oxygen. Oxygen can oxidize your aluminum wheel, and to some degree the rubber in your tire. It's a slow process usually, although sometimes aluminum can get screwed up pretty badly out in the weather. Inside your tire, though, the advantages would be marginal. To be honest, I have never seen any evidence of oxidation inside a tire. I don't think it's much of a problem.

Your beliefs let you down, Bob. Nitrogen is smaller than oxygen.

Just going from what I read, it's the moisture in ambient air that amplifies the pressure variations due to temperature changes. Processed nitrogen is inherently dry. If what I have read is true, you can get the same benefit by putting a good dryer system on an air compressor to cut down on moisture content and using dry air instead of normal (moist) air or nitrogen. Someone else mentioned that oxygen in air degrades the rubber and metals over time. Also moisture would do that, so there would be benefits in using dry air from that standpiont too.

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')

That would violate the laws of physics. The correct statement is that nitrogen does not vary AS MUCH with temperature as air does.

Yes. First, air is mostly nitrogen so the sealing against aluminum rims claim is bogus. Second, unless you're driving a race car where 1/2 psi will make a noticeable change in the handling of the car, its just dumb to spend $5 on air for your tires.

What short memory you guys have:

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Subject: Nitrogen tire filling arrives in Calgary (CostCo) Date: Sat, 02 Oct 2004 09:49:25 -0400 From: MoPar Man Newsgroups: rec.autos.makers.chrysler

Experts say that nitrogen molecules are four times larger than oxygen. Retailers say tires with nitrogen should stay inflated four times longer, maintain a consistent tire pressure and increase its life span.

Nitrogen tire filling is already widely used in Europe. Costco doesn't charge any extra for the gas, which is included in the price of the tire and installation.

Nitrogen -- a dry, inert gas used by racing professionals and the U.S. military to inflate racecar tires and military vehicles, respectively

-- leaks through a tire's rubber walls three times more slowly than oxygen. As a result, tires filled with high-quality nitrogen delivered by IR's system stay inflated longer, which allows them to grip the road better and provide greater control in all weather conditions.

"It's an obvious safety issue," said Ray Evernham, a three-time NASCAR Nextel Cup champion crew chief, team owner of Evernham Motorsports and an IR spokesperson. "Simply put, tires filled with nitrogen provide more stable pressure. That's why IR's Nitrogen Tire Filling System represents the best solution for drivers and tire-repair centers."

(and part of the same thread)

Bill Putney wrote:

I wonder if nitrogen-filled tires play any role in preventing leaks on aluminum rims or reducing rust and pit formation on aluminum rims.

hmmm. I wonder what the "nitrogen experts" would say about that?

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Also see this:

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Subject: Re: Tires get an expirati> ... He says Ford's research into the Firestone problem showed

An argument that seasonal tires (still mounted to wheels) should be stored with the air taken out of them (ie deflated) ?

Also an argument that tires be filled with nitrogen? Perhaps some other gas?

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If you are driving a NASCAR vehicle in competition at 200 mph, I'd strongly suggest nitrogen in your tires. Otherwise, you will be quite satisfied by checking and adjusting your tire pressure on a weekly basis.

You shouldn't be concerned about the minor fluctuations in air pressure caused by the moisture in your tires. It just isn't that important for the average driver. And the oxygen attacking the outside of your tires and alloy wheels is a much bigger concern that the oxygen attacking the inside. Remember: There is a finite amount of oxygen inside your tires, whereas the outsides of the tires and wheels have a nearly infinite supply of oxygen (and salt and water).

True, but it's also monatomic and really, really small, so you may experience some leakage...

I think some really hard core bike racers were trying this maybe 10 years ago. Since I'm not really part of that scene I don't know if it ever caught on or was just something a couple guys tried to get an edge.

nate

snipped-for-privacy@comcast.net wrote:

The helium molecule is small and very flexible,. Unless your tire/rim are VERY securely sealed and the tire itself is tight in the extreme, helium would migrate right through the tire and leak into the atmosphere far quicker than just straight air.

Unless your tire/rim are VERY securely sealed and the tire itself is tight in the extreme, helium would migrate right through the tire and leak into the atmosphere

____Reply Separator_____

Causing everyone in the area to talk like Alvin, Theodore and Simon.

Yes. PV = nRT.

DAS

For direct contact replace nospam with schmetterling

Well then - guess what that means. It means that if you fill a tire with air, that in a few months, the smaller molecules will have selectively been filtered out, and the concentration of nitrogen will greatly increase through "natural slection". Adding some makeup air over that first few months to make up for the exiting of smaller molecules will be adding a smaller percentage of overall smaller molecules, so you will be asymptotically approach 100% nitrogen over the course of, what, 6 months to a year.

I've got three year old tires on my car - originally filled with air. They should be about 95+% nitorgen-filled now.

I still think the cause of the instaneous temperature/pressure effects are the moisture in typical compressed ambient air vs. dry air or dry (commercial) nitrgogen.

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')

This is a big bunch of horseshit. Doesen't anyone know math anymore?

Let's see, even assuming that a molecule 4 times larger leaks through rubber 4 times slower (which is preposterous malarky) since air is 78% nitrogen, only the 22% oxygen component in air would be leaking out at 4 times faster.

If you inflate your tire to max inflation pressure - which for most tires is 35psi - then even if all the oxygen leaked out the pressure drop on the tire is only going to be 7psi, which will drop the pressure to 28psi which is still well within the manufacturers recommendations for most passenger vehicles.

In my vehicles I see about a 2 psi loss every 6 months - do these nitrogen bozos think I'm going to stop checking tire air pressure except at 2 year intervals?!?!

This rubbish was debunked back then in this group as well as the oxygen migrating through the carcass bullcrap..

Ted

This is almost as good as the poor sucker who phoned up Click and Clack to ask if the air in his tires should be changed. Apparently, someone had told him that the air gets worn out and goes hard over time -- so it needed periodic replacement!

I'd go with standard air so eventually the heavier molecules would be expelled thru the tire body simply by centrifugal force.

;-)