Nitrogen Instead of Oxygen??



Ummm, ya, old news.
Dunn tire offers it.


the main difference comes down to nitrogen molecules being larger than oxygen molecules… but not worth it for a soccer mom to put in her van.

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I’m actually developing a nitrogen generator at work right now to be included in envirolube express vans. It’s a bunch of BS, but I just design what my boss tells me to. :gotme:


I really don’t see how he got an increase of 5% gas mileage vs. checking cold tire pressure bi-weekly. I do see a benefit for those idiots that run around with 70-series looking like 30 series.

I have been considering this for the NX. After a 15 minute session pressures went from 31 to 45. $2 a tire is almost worth taking guess work out of it.


But the comparison is air to nitrogen, not oxygen to nitrogen. Anyway, they’re similar in size. Although nitrogen’s electrons are held a bit more loosely due to the smaller nucleus.

And actually, the electrons in oxygen experience a bit higher repulsion between eachother than they do in a nitrogen molecule. But then, this doesn’t matter as much since they’re both diatomic…bottom line, size doesn’t matter here…

There are, however, a few elements in regular air that are smaller than oxygen or nitrogen.

A benefit I can think of would be moisture. Given that it’s “pure” nitrogen, there wouldn’t be any water vapor in there. And the tires wouldn’t be prone to oxidation-reduction because, well, there’s nothing to oxidize if you can’t move the protons around.

But this has been discussed before and it’s really not important for your regular street going person.


AIR (which is aprox. 78% nitrogen, 21% Oxygen, and 1% diarrhea) when replaced with 100% nitrogen essentially, ignoring the diarrhea comes down to a difference between oxygen and nitrogen

going back to my original point, nitrogen molecules are ‘more massive’ and when trying to permiate through rubber it is 3 to 4 times slower.

Nitrogen has more mass, so it migrates through the tire slower. The result: Tires hold their psi longer, making it more ‘stable’.


True, Nitrogen is inert and does not have the corrosive properties that straight air does. But what about the outside of the tire? It is still being exposed to a 78% 21% 1% mixture.

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If you assume that theory holds true, then as you continually top off your tires as oxygen permeates through the rubber faster, you are essentially over time obtaining an enriched level of nitrogen in your tires.

Unless you apply a vacuum to an empty tire and fill/purge/fill/purge you will likely not have more than 90-95% pure nitrogen anyways.


I’ll keep filling my tires with 78% nitrogen.




Its good for supersonic aircraft, but for most airplanes, helicopters and slower things, its just silly.

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Not a total gimmick, but for street cars yes I would say its a waste of money. We use nitrogen in our airplane tires. Reason for it is the temperature at cruise altitudes is roughly -60 degrees F, so using just regular air isn’t gonna cut it. Constant tire pressure at all temps ftw.

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No, nitrogen does NOT have more mass. GMW of diatomic nitrogen is 28.

GMW of diatomic oxygen is 32.


Josh, you are being naughty confusing mass and volume… Didn’t 11th grade Chemistry teach you anything?? hahahhaa…


The reason that you would lose less pressure over time with pure nitrogen vs air is that nitrogen molecules have a larger kinetic diameter, so it won’t seep through the rubber as quickly/easily as oxygen.

I’m actually not totally clear on why nitrogen changes less than oxygen volumetrically when temperature changes. Corey? Josh?

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Correct me if I am wrong but the diarrhea tends to plug the pores of the tire thusly keeping the air trapped inside the tire.
It works like FIX-A-FLAT.

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correct… "No, nitrogen does NOT have more mass. GMW of diatomic nitrogen is 28.

GMW of diatomic oxygen is 32."

volume is what i should have said … since the passing through a substrate (rubber) is limited by its size, not weight.

i think you need to revert back to V=nRT/p

I believe, Nitrogen is a more tightly packed compressed gas and therefore more stable.

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Diatomic nitrogen is triply bonded, whereas oxygen is doubly.