Friday, July 30, 2021
Friday, July 30, 2021

Is it worth it to inflate tires with nitrogen?

RV Tire Safety
with RV tire expert Roger Marble

Regarding nitrogen (N2) passing through (permeating) tire rubber more slowly than oxygen (O2) due to molecular size, are nitrogen molecules really larger than oxygen molecules? According to the Get Nitrogen Institute in their paper on N2 effusion“The correct answer, with respect to ‘permeation,’ is yes.”

So I imagine your question is: Why don’t I support the effort to “sell” the idea of always inflating your tires with just nitrogen? It comes down to effort and cost versus level of benefit.

Maybe one way to think of this would be to imagine dropping a penny as you walk away from making a small purchase at a store. If you dropped a number of coins you might stop, bend over and pick them all up. But what if you only dropped one penny and didn’t discover the fact until you had walked to your car. Would you walk the 20 feet back to the store to look for the penny? I bet not. There is no doubt that you would have more money if you picked up the penny, but would you consider it worth the effort?

In general, tires lose about 1%  of their inflation pressure each month in laboratory testing. This is almost entirely oxygen. It is also true that tire pressure changes about 2% for every change in temperature of 10 F. This is true for nitrogen or air.

I haven’t tried to run a test, but it is also true that every time you use a hand pressure gauge to check your air you let a little air out. How much air do you let out if you use a gauge to check your tires every day? Might it be 1% in a month’s time? Might it be more?

Finally, what does it cost to inflate your tires with N2? Even if you have a deal with a dealer and can get your pressure “topped off” for free, you still have to drive to the store location to get that “free” inflation.

Bottom Line:

IMO, the small level of benefit of inflating tires with N2 just isn’t worth the effort and cost. There is also the real negative of not checking your tire pressure simply because you believe that by inflating with N2 your tires will never lose pressure so you don’t need to check. What about small punctures or leaking valves? If you don’t check the pressure you will not learn about the leak until it is too late.

However, if you want to inflate your tires with N2, I see nothing wrong with doing that. After all, it’s your time and money, not mine.

Read more from Roger Marble on his blog at





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3 years ago

The key for me is the fact that “N” (Not N2) is DRY! I live in FL and every shop air hose here has water dripping out the end of it.

3 years ago

Doesn’t matter to me as I have an air compressor to use with my Motorhome. Wouldn’t mind having them inflated with nitrogen but after that, I would only be adding it would become moot, I would think. Now it would be great in my bicycle tires.

Keira RVer
3 years ago

Oxygen is a highly reactive gas. Nitrogen is an inert gas, so is non reactive. The 20% oxygen in standard air does cause some reaction with the rubber inside a tires. The rubber will degrade more quickly with oxygen in the mix. Presumably your tires will last longer if you inflate with nitrogen.
I have not seen studies that show how much degradation you get with oxygen versus nitrogen. Has anyone seen any scientific research on this?

3 years ago

I thought “Nitrogen inflation” was a joke like “changing your summer air for winter air”… Didn’t realise anyone was actually selling this as a serious thing. Thanks for the laugh!

3 years ago

By volume, dry air contains 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, and small amounts of other gases. Air also contains a variable amount of water vapor, on average around 1% at sea level, and 0.4% over the entire atmosphere.

Personally I have questioned for years what the purpose of putting nitrogen in tires might be since the air we normally put in is about 80% nitrogen anyway – what difference could it make? And why would NASCAR worry about air loss when the tires aren’t even on the car more than about an hour or so? The whole thing just seems pointless.

Tommy Molnar
3 years ago

When I used to buy tires from Costco, they would inflate with them nitrogen. That’s fine if you always have Costco nearby to keep the pressure up. But, once we leave town, that’s the end of finding a Costco – at least where WE travel. Then I’m filling the tire(s) with a normal pump – and everyday air. So even if it’s a great idea, it doesn’t work very well for my lifestyle.

3 years ago

Why do NASCAR drivers use nitrogen in their race cars if there is no advantage? I usually buy my tires at Costco and they put nitrogen in the tires they sell which I find has helped my trailer tires pressure drop better than than just plain air.Many tire dealers,like the monopoly we all know about in the Pacific Northwest,won’t use nitrogen because they are too cheap to install the equipment. But…there is no substitute for checking tire pressures every time you hit the road.

Mike Sokol (@mike)
3 years ago

Glenn, sorry but all gasses follow Boyle’s Law and their pressure in a constant volume system will increase or decrease as the temperature increases or decreases. However, there can be big volume changes as a gas condenses to a liquid state around its vapor pressure point. That’s how refrigeration works, but there’s no pressure change from this phase change. The liquid/gas phase change is the result of the pressure change, not the other way around. I took classes on this back in college for engineering:

3 years ago

Good discussion, Roger. As I said in reply to Glen on the temperature/pressure relationship, air is 80% nitrogen and only about 20% oxygen ( a couple of other gases like CO2, Ar, etc). So as you say, given the permeablilty difference and only 20% oxygen, there is not much gain with pure nitrogen. But also as you say it can’t hurt and its not my (or your) money.

3 years ago

The reason I use nitrogen has nothing to do with permeation. Nitrogen is an inert gas. This means that there is no change in pressure with temperature increase or decrease. What I inflate a tire to is what it stays at. As a hvac mechanic I have small tanks of nitrogen handy at all times. A regulator and tire chuck and I’m good to go. Nitrogen is cheap and handy.

3 years ago
Reply to  Glenn

Sorry, Glenn, but all gases fallow the gas law, PV=NRT, where P, pressure is directly proportional to T, temperature with a constant V, volume. And don’t forget, air is 80% nitrogen and about 20% oxygen.

3 years ago
Reply to  Merl

I disagree. The reason we use nitrogen for leak checking refrigeration lines is that it will not change pressure with temperature change. If I leave a line pressurized to 400 lbs on a warm afternoon and come back on a cool morning and it is still at 400 lbs I know I have a sealed and leak free system. May have a 30 to 40 degree drop in temperature overnight but no change in pressure.

Colin Grant
3 years ago
Reply to  Glenn

The reason to use nitrogen is because it doesn’t introduce contaminants like air would for HVAC or tires. Race tires don’t want water from air. It is also inert and has a quicker heat dissipation but it does expand and contract as all gases do but a small volume appears not to change. If you had very sensitive gauges accurate to 1/100 of a pound you would see the change.

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