Does Using Nitrogen In Filling Car Tires Worth It?

There have been a new trend worldwide in filling car tires with nitrogen instead of normal air. Nitrogen companies have been marketing nitrogen as the ultimate substitute to normal air in filling car tires. The main media pushing towards the use of nitrogen was the advantages of nitrogen told and tested by nitrogen companies themselves, suspicious isn't it? especially when it costs around 50 $ to have a full nitrogen set in your 4 wheels. The question you would probably ask yourself is: Does it worth it?.


Short answer: No (Unless you are a formula 1 driver or NASA mars explorer designer and you want to spend a lot of money to gain minor advantages that aren't even noticeable).

To state things clear, normal air contains around 78% of it's constituents as nitrogen. Nitrogen is the major component of normal air so if you are looking for a difference, you are just trying to manipulate the effects of the remaining 22% of air which is oxygen, carbon dioxide, and other minor gases plus the normal humidity in air.

So Let's discuss the advantages of nitrogen and I will let you decide if they are really for real:

1- Nitrogen is lighter than air:

That's true on molecular level which means lighter tires and less fuel consumption but considering the previous fact that air is 78% nitrogen, and the fact that air itself is the least affecting component of tire weight (considering tire materials like rubber, iron filling, rims, screws) air would make a very minor weighing component of the whole tire set and you are just trying to lower only 20% of that minor component. So in fact, nitrogen makes no differences in overall car weight.

2- More stable tire pressure:

Due to the fact that pure nitrogen contains no humidity and water content so they say it is less liable to pressure changes than normal air. That's a myth because nitrogen is like any other gas, it expands with heat and shrinks with cold temperature. There is no such thing as stable gas pressure according to physics unless you keep the external temperature constant (which is impossible to control the atmosphere) so nitrogen is liable to pressure changes with external temperature changes. 

3- less fuel consumption:

Due to the previous fact number 1, nitrogen makes a very minor difference in fuel consumption or no difference at all. In fact, the money you spend for nitrogen will out cost the money you save by filling nitrogen.

4- Less tire gas leaks:

Nitrogen gas companies claim that nitrogen molecule is larger than oxygen molecules which makes it less liable to leaks from minute holes in tires. So let's think again, nitrogen companies claim that (Big) nitrogen molecules will not pass through (Small) tire holes but oxygen molecules will do. Let's state things clear here, nitrogen molecules size is 300 picometer while oxygen molecules are 292 picometers. The picometer equals 1/trillionth of a meter and there is an 8 picometers difference between both molecules. This very very minor difference between both makes no difference at all on practical level and in fact if you have any holes in your tires then both air and pure nitrogen will leak the same from these holes which would be larger by millions of times than the 8 picometer difference between air and pure nitrogen. 

5- More stable at turns:

Due to the myth that nitrogen pressure is more stable than air pressure, nitrogen gas companies claim that nitrogen makes your car more stable at turns. As we discussed in fact number 2, all gasses have physical properties that go the same with more or less temperature differences plus the fact that all tire pressures rise around 5 psi at the end of the day due to increased tire temperature by tire friction with road asphalt and the increased car heat due to engine heat and external environment heat. So nitrogen will not help it at all and on practical level, nitrogen filled tires increase the same average 5 psi over day's work as the usual air tires.


So to sum up the whole article, nitrogen makes no difference at all and unless you are a professional race driver who cares about the 0.001 second differences then you shouldn't waste your money on nitrogen. Final advice is to calibrate your tire pressures at least once monthly to keep your tire pressures stable as normal tires would go around 1-2 psi fewer per month. 

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