Inflate with Nitrogen? Why?

Saw this question on a FB page.

" Anyone researched cost etc of replacing the air in our tires with nitrogen? It's more stable and does not change pressure with temps. All my BMW's have it. I hate checking my pressures every trip.

There were over 10 pages of replies. Some good some not so much. Here is my final answer.

Lot of time and effort in this thread but I am not sure if a consensus will ever be reached.

As a tire design engineer I can say that inflating tires with Nitrogen AKA "N2" will not hurt the tire.

Is it better for the tire? Theoretically yes as N2 is less reactive than O2 but this gets sticky when you ask if the benefits are measurable or meaningful for an RV or other street vehicle in normal operation.

I do not see where any poster of this thread has identified any problems with their tire due to Oxygen reacting with the rubber in their tires.

Let me throw a "fly in the ointment" into this topic. Those advertising the use of N2 offer a claim of improved fuel economy. However I believe this claim is based on a couple of assumptions:
1. That the average driver does not check the air pressure in their tires and with O2 levels decreasing due to the O2 reacting with the rubber which effectively lowers the tire pressure over time.
2. Lower tire pressure means worse fuel economy.
I accept and agree with those 2 assumptions
BUT With the advent of TPMS many RV owners are now properly paying more attention to their tire pressure so they are not driving with their tires at lower pressure, so what is the advantage?


I believe I can even posit a disadvantage to running N2.


If we assume, that tire pressure does not change (increase) as some advocates of N2 claim, then that would suggest tires inflated with N2 will deliver worse fuel economy as the tire running at a lower pressure than tires inflated with air, will deflect more which means it will deliver worse fuel economy. This worse fuel economy would be very difficult to measure but the fact that tires with lower pressure deliver worse fuel economy is established and accepted fact.

For me, as a tire design engineer, I feel that using N2 instead of Air to inflate tires MIGHT be beneficial to long term tire life if no effort is made to ensure you are not introducing excess moisture into the tire air chamber. If you make the minimal effort to control the moisture level.That means your air compressor tank is properly maintained and drained of the excess moisture that can accumulate in the tank, or you use a "tank-less" compressor so the only moisture introduced into the tire is the moisture in the air we are breathing.

I have a post in this blog on how to get unlimited dry air for your tires for a few dollars no matter what compressor you use. Make your own air dryer using components used in auto painting and place it in your air line so all your high pressure air is relatively dry. 

In case people are wondering what I do... I have a large air compressor in my shop. I drain it every time i Use it. I also have an "air dryer" in the line to protect my air tools from rust due to moisture. I also have the "dryer" I made in the link so I see no reason to use Nitrogen in any of my tires.

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