Originally Posted by tacomataco2
Nitrogen is an inert gas, it does not expand or contract. Therefore the pressure of a tire filled with nitrogen doesn't change with temperature like air does. It is much more expensive and if you add air to it, it basically ruins the whole 'nitrogen filled' thing.
You can use a regular air gauge to read the pressure. But don't bother with it, just check your tires at each oil change. Complete waste of time in my eyes.
Go back and review basic science.
An inert gas is CHEMICALLY non-reactive. It does not support oxidation, and it is used in aircraft because if a tire blows in the wheelwell, it will aid in quenching the fire rather than adding more oxygen to the process.
ALL GASSES, LIQUIDS, AND SOLIDS EXPAND AND CONTRACT WITH HEAT AND COLD. THIS IS BASIC ELEMENTARY SCHOOL LEVEL PHYSICS.
Some gasses have a higher or lower coefficient of expansion, and nitrogen is SOMEWHAT more favorable than oxygen, but the difference between pure nitrogen and "air" is not measurable, given that "air" is already about 80% nitrogen.
There is a lot of bullshit being fed to people by Nitrogen equipment salesmen.
The air that we are sitting in is already about 80% nitrogen... yet I had a moron at a tire shop try to tell me that "we can breathe" because the oxygen is down here at the surface, and the nitrogen stratifies at high altitude and that's why they call it the stratosphere.
There is a MINOR benefit to nitrogen inflation in that it will reduce corrosion of the wheels because of the lack of oxygen, and the nitrogen systems are running proper driers and not adding water vapor with the nitrogen fill.
Tire life is not increased. Tire oxidation occurs on the exterior from exposure to UV and ozone. Nitrogen does nothing to reduce that.
You still need to check your tires regularly with nitrogen. The molecule is slightly larger than oxygen... but if there were a significant difference, then realize that if you find an air-filled tire down 5psi, then you would assume that 5psi was the oxygen and not the nitrogen leaking out.
You had 35psi in the tire and lost 15% of that pressure, meaning that you lost 15% of your gas... and if what was lost was all oxygen, then that means that you are now running only 5% oxygen and 95% nitrogen.
Each time you top off with air, you are reducing the amount of oxygen.
But that is not the case. The membrane systems used to produce nitrogen are not the same as a tire. Nitrogen leaks out of a tire just as quickly as "air" leaks out of a tire.
Nitrogen inflation DOES NOT HURT anything.
Nitrogen inflation is not worth paying for. If you get it for free, accept it, but don't worry about it, and you can top off with air.