I have heard several arguments in favor of using nitrogen in tires, but the the final analysis seems to be “It is a good thing, but not worth much money. If you are getting nitrogen for no extra cost (e.g. Costco) great! If they charge more than a couple of bucks per tire, no thanks”
I have been looking at forum posts regarding tire pressure sensors, and I note that when people cut open failed sensors, they sometimes find corrosion that likely led to premature battery or circuit board failure.
I know that nitrogen is completely dry, because when you separate the nitrogen from air, you also remove the water vapor.
Does it not therefore follow that keeping the water vapor out of my tires might also help preserve my sensors (which cost $30 to $120 ea plus installation)
Perhaps this argument has been made before, but I had not heard it.
I’d imagine the corrosion is caused by the battery chemicals, not water vapor. But could be…
The good sensors are completely potted to seal out moisture. The cheap ones are not.
If the compressor you are using to fill your tires has been drained and fitted with a water separator, your tires should have dry air. You can add an additional moisture trap at the outlet (normally used for spray painting) to remove the last bit.
I retired after 17 years from the biggest automotive tire manufacture in the world, I worked on the retail/shop side of things, trust me, if it was that beneficial, we would have used/sold it, because in the daily driver world, it is nothing more than a money grabber and or gimmick to get you to buy their tires…
In the racing world, it does maintain the pressure more consistently under changing temperatures…
My guess why manufactures/dealers use it, is so they don’t have to keep adjusting the tire pressures to keep the TPMS lights from coming on and freaking test drivers out… lol
Sensors seem to last over 10 years
I doubt using nitrogen could drastically increase that
Yepers, the ones in my 2009 Vibe/Matrix are all factory installed and still working last time it was driven (knock on wood), might not be the next time, but that is for another day… lol
If tpms goes off as it sometimes does for low pressure I just use my 12volt pump and don’t even think about it on my green capped tires.
For regular passenger vehicles Nitrogen means almost nothing . Besides regular air is 78 % Nitrogen anyway and just a way for tire stores to make you feel better.
Air (78% nitrogen, 21% oxygen, 1% argon) is an ideal gas at tire conditions. Pure nitrogen is also an ideal gas under those conditions. Air or nitrogen responds exactly the same to changing temperature, following the ideal gas law (PV=nRT).
Water vapor, however, is not an ideal gas under those conditions. It can condense or evaporate, as temperature changes, causing a dramatic fluctuation in tire pressure.
Nitrogen is used in race cars and aircraft tires because it is absolutely dry, and because in the event of a fire, an exploding tire filled with nitrogen will tend to extinguish, rather than fan, a fire.
I look at nitrogen in tires the way I look at these ridiculously huge spoilers or wings on the back of compact cars:
Sure, there may be a big difference in performance at consistently high speeds, or on a racetrack, or in professional racing situations.
But your little “enhanced” Honda Civic is not that car, friend. You’ve wasted your money trying to impress your buddies. That’s the real story here.
So all you stem folks, what is the percentage of nitrogen in plain old air again? I forget, 70, 80, 90%?
As @Manolito said, about 78%. In more detail:
| Gas | Formula | Percentage (%) |
|---|---|---|
| Nitrogen | N2 | 78.084 |
| Oxygen | O2 | 20.946 |
| Argon | Ar | 0.9340 |
| Carbon Dioxide | CO2 | ~0.04 |
| Neon | Ne | 0.001818 |
| Helium | He | 0.000524 |
| Methane | CH4 | 0.000187 |
| Krypton | Kr | 0.000114 |
| Hydrogen | H2 | 0.00005 |
| Xenon | Xe | 0.0000087 |
| Ozone | O3 | 0.000007 |
| Nitrogen Dioxide | NO2 | 0.000002 |
| Iodine | I2 | 0.000001 |
Actually, some manufacturers add spoilers to the car to improve aerodynamics. This improves fuel economy.
https://www.cars.com/articles/what-does-a-spoiler-do-424902/
Tester
Water is a little over 1% by weight for sea level air at 60% relative humidity.
Correct, but just to be clear, the other posts were referencing dry (lab) air, and were in units of volume (molar) percent. Weight percent and volume percent are slightly different due to the individual molecular weights of the gases.
Wow, this thread really took a turn. Probably my fault.
I think there are too many variables that can affect sensor life, most notably the quality of the sensors themselves.
My daily driver is a 2013 with 147,000 miles. Still has all 4 original sensors. My wife’s car is a 2018 with 75,000 miles. It has 2 dead sensors. Neither of the cars have nitrogen fill.
Nitrogen in tyre-lobby gives disadvantages like availability, but further only advantages.
These advantages are often based on false facts, and many true ones can be relativated.
Will begin with one here. Can give more
Written is that ( 100% , HAHA) Nitrogen filled keeps tire cooler.
Prove then given that Nitrogen absorbs 13% more energy to rise 1 degr ( F, C, K, R whatever) per gramm.
Now tyres are filled wih a vollume and not weight.
What should be used is Joulle/ mol/ degr .
1 moll of any gas takes the same space, and weighs the moleculeweight in gramms.
Nitrogen N2 weighs 28 gram/ mol
Oxigen O2 weighs 32 gr/ mol.
Do then 32/(28x 1.13)= 1.011, so Oxigen in vollume absorbs a good 1% more energy to rise 1 degr.
So this selling argument is simply not true.
Retired pilot here. The reason it’s important to use dry air in aircraft that fly at high altitudes is this. It’s very cold at airline altitudes. If you had some water inside your tire it would freeze. Then when you landed it may create an out of balance condition.
Light aircraft like the Cessna 150 I learned to fly in don’t have this problem and we use normal air.
Long Version: Barry’s Tire Tech:Nitrogen Inflation
Short Version: Water vapor and oxygen leak INTO tires. That’s because of the Law of Partial Pressure of Gases which says that gases not present in the air chamber of a tire will leak back into the tire to try to equalize the partial pressure of that gas in the surrounding atmosphere. Don’t forget that tires are very slightly porous.
Further, water vapor, aka steam, obeys the Ideal Gas Law except when condensation or boiling takes place. That just doesn’t happen inside a tire except when subjected to very cold temperatures - such as with an aircraft. Note that you never find water inside a tire when dismounting an old tire.
So what happens if there is water in a tire at the start? It eventually evaporates. The fact that it does so slowly is why racing tires use nitrogen - not enough time!
As far as the sensors go, the length of time it takes for the water vapor to leak back into the tire is short enough that it would have little effect on the corrosion rate of the sensors.
So its not an absolute rule to use pure Nitrogen filling in airplaines. Thought it was.
The influence of water is also often exagerated, and sayd by the Nitrogen -lobby, that it rises the temperature of tyre.
But with water in tyre, the presdure rises a bit more, but temperature of gascompound stays a bit lower, and with that the temperature of tyre-material stays a bit lower.
Main goal of pressure-determination, is to give the tyre a deflection, so heatproduction a cycle, that wont overheat any part of tyre-material.
Suppose if 100% Nitrogen in tyre ( impossible) under same riding conditions and same cold pressure, the tyre inside gas ( no compound)rises to 75 degrC/ 167 degrF.
Then with humid air filled, the pressure rises 0.36 bar/ 5.25 psi more, and that extra is extra gas to cool down the tyre-material. The higher pressure gives lesser deflection, so lesser heatproduction at same speed.
This together gives a lower temperature in tyre, and with that of tyre-material.
Cant calculate it exactly, because lower temperature means lesser water as gas in tyre, wich gives a tyny bit more deflection, so more heatproduction.
I estimate, it balances out at 72 degrC in tyre, and tyre-material not 120 degrC/ 248 degrF , but 119 degrC of tyre-material.
All marginal advantage for humid air, but again certainly no pro for Nitrogen filling.