Nitrogen in Tires

OK, here is a quote from

"Oxygen molecules, which are smaller than nitrogen molecules, seep through three to four times faster. A tire filled with "plain old air" will lose 1.5 psi in less than a month; with nitrogen, this can take six months or longer."

BTW, they also say that the FAA requires that tires on all commercial aircraft be filled with nitrogen.

Yeah...maybe. And, what's in the tires won't always be the issue anyway.

Here we are talking about an edge that can only be seen in an electron microscope and only be felt under the extremely adverse conditions of racing, it's not an edge. It has nothing to do with 60% of drivers it has nothing to do with .0001% of drivers, maybe 2000 drivers in the world would benefit from it and they drive cars so expensive they can't waste time on newsgroups for fear of missing that tear in their cars platic statis bubble.

When was the last time you heard someone say, "Geez, if only that gamma ray hadn't punched that Oxygen sized molecule hole in the side of my tire, I know a Nitrogen molecule would have just plugged it up!" They invent stupid things because they belive we are stupid enough to buy them.

I think the fact is, what's in the tires isn't the issue. How may times have you hit the curb while parking? Damaged rims, poor valve stems, worn out tires, these are the things that cause problems, not the gas used.

This may be true but mind the source. They have a vested interest in selling nitrogen.

I'm sure that has to do with extreme temp changes and high altitude, things that your normal passenger car doesn't need to deal with... At least one would hope that to be true.

Even more insidious: The aluminum rims on my Tacoma have enough corrosion where they meet the tire that each tire loses between 10 and 15 pounds a week. The dealer says "never heard of such a thing". Three mechanics say "Yeah...that's why we have that angle grinder there on the tool rack".

Right - and you are getting rid of virtually all the oxygen in the tire air with the usual Nitrogen Generator equipment, to over 98% nitrogen - 99.5% if the molecular sieve is running perfectly. And the good systems are running the air through a dessicant drier step at the same time, to remove almost all moisture from the nitrogen.

-->--

This contradicts the physical law that state that the time required for effusion of gases is proportional to the square root of its molecular mass.

Hammo

There is a lot of controversy about this, mostly on the theoretical side versus those who have tested it. But one thing to consider is the law of physics that you state (Grahams Law) only applies to gases go through a hole where no other gases are present. What we are discussing is how these molecules permeate through rubber, not in-between the tire and the rim (or other hole).

The EPA has apparently bought off on the idea in a newsletter:

"Nitrogen inflation systems help maintain tire pressure because nitrogen does not permeate through tires as readily as air does."

Bridgestone apparently also agrees:

"While both nitrogen and oxygen can permeate rubber, nitrogen does it much more slowly. It might take six months to lose 2 psi with nitrogen, compared to just a month with air."

I am not a scientist and have not conducted any studies myself. I am just reporting information that others have published.

Nitrogen is just the latest addition to the dealer 'smoke and mirrors additional profit package.' It must be getting harder to sell the good old door edge guards, rust proofing, paint stripes etall than when I was in retail. We loved to sell those fake roofs and gold packages for an additional $2,800 gross on a Camry, as well. LOL

mike

Not to worry, today cars have tire PSI alarms ;)

mike

At lease some tire stores use nitrogen at no additional charge.

So, this brings us back to the thought that, after 1.5 months, there is more Nitrogen that any other gas in the tires. So why pay extra?

True. But the largest retailer of tires in the U.S. provides that nitrogen at no extra cost. They don't do it just to be nice. They realize that the result is less warranty repairs due to under-inflation and deterioration. Unlike most tire store chains, Costco actually does honor the manufacturer's tire warranties.

I've heard good things about Les Schwab, but they don't have any stores in my area.

Sorry, I can't agree with your assessment of how the law is used. If you want to determine partial pressures related to effusion, it can be calculated.

Permeate is different from effusion in what way?

Is this based on the "size" of the molecule? See above....

Can't open it.

It is more to do with a dry gas used to inflate the tyre. This has merit, and obvious advantages in the minor applications they mention. They are slim on facts, and use a slick advertising method to sell it.

Information or spin?

Hammo

Permeate is moving through another molecular structure like rubber. Effusion is moving through a hole.

However, I don't really want to argue the theory. What I said is that the EPA and Bridgestone both repeated the assertion that nitrogen permeates rubber slower than oxygen. You can argue the theory all you want, but it would be a lot easier to just test it.

Bridgestone quoted some numbers in the link I posted, so maybe they did measure it (the loss of psi over time depending on whether the tire is filled with air or nitrogen).

"While both nitrogen and oxygen can permeate rubber, nitrogen does it much more slowly. It might take six months to lose 2 psi with nitrogen, compared to just a month with air."

If you have a problem with this, please contact Bridgestone..

I don't trust information coming from any car company that sells sizzle instead of steak in their ads.

It's bad enough we have an entire section of the Sunday Tribune devoted to GM called 'GM Overdrive'. Where's the equivalent Toyota section? They don't need one. . . .

First rule of understanding advertising. Beware of anyone trying to sell you the sizzle instead of the steak. That usually means that they don't have any real steak to sell, just some ground-up tripe they're trying to make you think is steak.

Charles of Schaumburg.

Bridgestone is a tire company, not a car company. The article was in Real Answers Magazine at the Bridgestone Truck Tire website.

The other post was from the EPA (Evenironmental Protection Agency) of the US Govt.

From all I've read about it, it seems to be another "service", designed more to lighten your wallet than anything else.