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A tire that has been inflated with nitrogen will maintain 'air pressure' much better and for a slightly longer period of time, as compared to a tire that has been inflated with regular air. This is because nitrogen molecules are larger in size than oxygen molecules and therefore, are less likely to leak or escape through the tire valve.
This indirectly, helps in bettering the fuel efficiency of the vehicle. This is because, insufficient air pressure in the car tire can have an adverse effect on its fuel consumption and resultant fuel efficiency. Nitrogen filled tires have better and more consistent 'air pressure' which consequently, aid the vehicle's fuel efficiency (even if it is by a small margin).
Pure nitrogen is much drier than regular air (which contains water vapor). Depending on tire temperatures, the water vapor in the air undergoes changes in pressure, which results in varying tire pressures. This is not an issue in case of nitrogen filled tires.
Oxygen and water vapor react with the insides of the car tire, i.e., with the rubber as well as the metal rims, and gradually lead to development and deposition of rust. This has an adverse effect on the longevity of the car tire. Nitrogen does not react with the car tire insides or with the rim, thereby enhancing the life of the car tire.
Nitrogen is a gas that does not support combustion, therefore in case of an extremely overheated tire catching fire, nitrogen makes for much better safety than regular air (which contains oxygen that supports combustion).
Filling nitrogen in tires also helps in keeping the insides of the tire cool, even at high speeds.

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It's a waste. Just check your tire pressure regularly. The tire doesn't care what it's inflated with, as long as it's inflated to the proper pressure.

1. Air contains 78% nitrogen already.
2. How do you get the air already in the tire out? You don't, so it isn't "pure" nitrogen.
3. What happens if you have to refill the tire and nitrogen isn't available? You add more air.
4. The sun (UV rays) break down the outside of a tire much quicker than a reaction in the tire. Most tires wear out their tread or are damaged beyond repair.
5. If the tire catches on fire, nitrogen is the least of your worries. Unless the source of ignition is inside the tire, not likely unless it has been punctured in which case forget the nitrogen "theory", the tire is going to burn very hot just from the outside air.
6. Properly inflated tires run cooler.

The moral of this story, it's a marketing gimmick. Just check your tire pressure once a month and you'll be fine. You'll find your tire pressure changes in regards to ambient temperature.


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Nitrogen in tires is terrific for the cash register at the place where they do it for you.

There was a local tire place that was advertising a job for a certified nitrogen installer. I called the state labor department to find out where I could get the certificate they wanted. They laughed at me. Geez, at 69 I was hoping I had found a new career.

In the 50s the phone company linemen used to put nitrogen in the multi wire cables on the poles on the theory that it displaced moisture. I don't know if it did, nor do I know if they still do.

I believe the current theory pertaining to tires is that it doesn't expand or contract so your tire pressure remains constant winter and summer. Since air is 78% nitrogen, just how much does that other 22% contribute to expansion anyway? Or maybe it does expand o.O

How are they going to evacuate all the air from the tire before they put the nitrogen in? Do they take them to outer space on the space shuttle? How long does it take to get your car back when they ground the shuttle for a year?


Any gas expands as the temperature increases so I don't buy that.

I do think it is a rip-off.

They just can't evacuate the tires before filling.


Some points I think a lot of people are missing on this.

1) The process of inflating tires with nitrogen is to deflate to 3 psi, inflate with nitrogen, deflate to 15 psi, inflate again with nitrogen. This does not give you "pure" nitrogen in the tire but it will be the 94% +. Its really not about adding nitrogen, its about removing the other components found in compressed air; water vapor, oxygen, dirt, oil, etc.

2) The tread life of the tire is increased, thereby increasing the useable miles on the tire. This is due to the decreased pressure fluctuation and improved pressure retention.

3) For the original purchaser of the tire, the tread may wear out before the interior breaks down, however the casing life is extended which allows for more retreads from a single casing. Retreaded tires use about 1/4 the oil to produce as new tires.

4) Nitrogen is a dry inflation medium. Water vapor is the greatest contributor to pressure changes as the tire heats and cools. By removing that water vapor the pressure remains more constant.

5) While regular pressure checks are a must, regardless of the inflation medium, studies by the National Highway Transportation Safety Administration have shown that 85% of Americans do not do so. For these people the benefits are magnified but nitrogen has been shown to help even those who do check pressure regularly, just not to as large an extent.

I was a skeptic until I tried it, now I'll never ride on anything else.


The machine that fills the nitrogen is the same one that evacuates the air out of the tire. No space shuttle required.