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Nitrogen in tires

Ok-been reading over the “nitrogen in tires” blogs here and haven’t seen this answer or question yet.

I’m buying a new TDI Jetta and the vehicle comes with pressure monitors and NITROGEN filled tires.

Question: Can I fill those tires with regular air at a filling station if I can’t find nitrogen somewhere on the road? Or do I always have to go to a nitrogen fill station?

Earth’s atmosphere is 78% nitrogen. Nitrogen in a street car (aka not a race car) is a marketing gimmick. Fill with regular air without another thought.

That’s what I thought…but wanted a second opinion!

Mleich is 100% correct. Air is about 78% nitrogen, 21% oxygen, and 1% argon and misc. Nitrogen in the tires is just a marketing gimmick and a revenue generating ploy.

Besides, those little green caps would make me feel like I was wearing a sign that said “here comes a sucker”.

You could fill the tires with carbon dioxide or any other gas and you’ll get similar results. The TPMS doesn’t care what gas it is, It only cares what the pressure is!

(OK, OK! May be a gas that attacks rubber would be a bad choice, but certainly any inert gas - and many other gases that are not so inert would work. The key would be not attacking the rubber and the metal of the rim.)


It’s also NOT MANDATED to use only Nitrogen to fill them.

Usually the need to air is eliminated with the use of nitrogen since it’s DRY and the lack of moisture content makes it unnecessary.

I haven’t had to add air to my wife’s tires (yes, my nitpicking fellow members, I’ve checked MANY times and still do) for about 3 years.

The place I buy tires doesn’t charge extra for it. It’s included with every tire you purchase. Big gimmick there.

You results have little to do with nitrogen, it’s the tires. There is very little difference in pressure stability in most cases. The CR tested for a year and found the following:

“The average loss of air-filled tires was just 3.5 psi from the initial 30 pressure setting. Nitrogen-filled tires lost an average of 2.2 psi from the initial 30 psi setting.”

Not much of a difference. Free nitrogen, fine, but paying anything for it puts it firmly in the “gimmick” category.

Before putting full faith in CR’s results, always (really) check their testing methods and criteria.

Take their infamous synthetic vs. conventional taxicab oil test. It’s heavily weighted in the misconception that taxi service is brutal and hard on engines. It’s not. Typically one warm up a day removes the most unavoidable wear that every engine sees. The shortened oil drain intervals have nothing to do with “SEVERE” and everything to do with an odometer being a poor measure of usage where you consume much fuel and travel few miles in a relative manner. Synthetics have nothing to do with longer engine life/reduced wear and everything to do with longer lubricant life …aka, reduced down time.

The whole premise of the test was flawed. The only thing it allowed was a relatively short time from beginning to end for data acquisition.

I was amazed at the claims being made for nitrogen, so I have extensively researched them and found a lack of foundation for just about all of them. The CR test quote was a convenient way of summarizing what I’ve found from a number of sources.

It’s amazing that cars never needed pure nitrogen for over 100 years…now of sudden it’s needed???

If it’s free…GREAT…if you have to pay for it…it’s a Gimmick…There is no substantial loss difference if using normal air (which is 98% nitrogen anyways) or using pure 99% nitrogen).

Even if it’s “free”, your still paying for it, right? It’s just not itemized.

Race car teams use nitrogen because of the consistent thermal expansion. Filling with air means a variable amount of humidity present and therefore a variable expansion rate as the tire heats up. This causes a variation in pressure and therefore diameter. Nitrogen makes the expansion rate consistent.

Nitrogen in street tires is a gimmick. Even if it’s not itemized, you’re paying for it in the price of the tire because the dealer has to pay for the nitrogen (therefore increasing his cost).

Don’t blame the dealers here too much, though. Someone at some point probably ASKED for the nitrogen because they saw that racers were doing it. Dealers then simply filled (no pun intended) the demand.

Actually, some chain shops are owned by race car owners, and figured selling nitrogen to tire buyers as a way of adding another profit adder. The rest saw the move and copied it. The sales pitch is pretty good, but a little research will dispel the myth quickly.

The thing people should realize is that race cars also use soft tires extremely sensitive to pressure changes and stress them to the max…then run them on the edge of disaster. And oxygen in the pits would feed a fire…nitrogen will not.

My guess is that it was the marketing guys that started this rethar than a customer request, but none of us will ever really know.

“…it’s the tires.”

I think it’s the valve stems, or possibly how the bead is mounted to the rims. That might be nit-picking, but I don’t believe it anything to do with the rubber.

And I suggest that free nitrogen may be a gimmick. If it gets you in the door and convinces you to buy their tires, it’s a gimmick.