Who knew! Damnit!

[AZCooWhip]

I made it easy and just switched to good old fashion plastic caps because I’ve aired down 300 or 400 times.

I‘m pretty sure I haven’t depleted all nitrogen my dealership put in. I’m actually due for a nitrogen refill this spring. I know what’s in my tires.

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[ShadowsPapa]

I made it easy and just switched to good old fashion plastic caps because I’ve aired down 300 or 400 times.

I‘m pretty sure I haven’t depleted all nitrogen my dealership put in. I’m actually due for a nitrogen refill this spring. I know what’s in my tires.

And if you lose one, or crack one in the cold (oh, wait, it never gets cold there), you aren't out anything. I mean, really, if someone is nitpicking about how your valve stem caps looks, well...........

 

[Rusty PW]

what's the benefits to fill the tires with nitrogen btw?

What's the benefits?........Hmmmmm........... to relieve you of the money in your wallet and to put it in someone else's wallet. This makes your wallet lighter.

 

[Rusty PW]

The problem is, people see nitrogen used in BIIG tires like on aircraft - to help mitigate the temperature/pressure fluctuations. However, how much fluctuation there is in pressure is also volume related. Bigger tires, lower pressures, bigger fluctuations. Car and small truck tires don't hold all that much air so fluctuations aren't as big/drastic, and aren't as catastrophic as on aircraft.

And take into account that the air we breathe is mostly nitrogen anyway, you are only replacing less than 1/4 of the non-nitrogen with nitrogen. 78% is already nitrogen in normal air
So you are only gaining that 22% - enough to matter?

There's a test that's supposedly online people can access - this talks about it.

In 2008, the National Highway Traffic Safety Administration (NHTSA) conducted a series of tests on the varying levels of nitrogen in tires. It sought to scientifically prove or disprove the hearsay about better performance and increased fuel economy when using nitrogen-inflated tires. Tires were inflated with either nitrogen or air and tested for 90 days, including static tests and rolling wheel tests.

These tests confirmed that using nitrogen does, indeed, slow pressure loss, but not at an entirely significant rate.
According to the study, pure nitrogen-filled tires do not respond as much to temperature fluctuations. That means that the tire pressure will stay more consistent – not only throughout the day, but as the tire heats up and cools during and after use.

But the differences in small tires isn't enough to offset the costs.

Tires that require very specific operating conditions, racing tires, aircraft tires that heat up really fast from the cold of above, that sort of thing, it's necessary.


I did some digging and found the caps like on my wheels are supposedly to indicate nitrogen - but they lack the N symbol on the end, so I have no idea what's up with that. Just that both trucks came to me that way, both with stock wheels, one with stock tires.

Didn't we have a 100 page thread on this subject not long ago?

 

[FKN Slayer]

It is my understanding that the green caps signify you have summer air in the tires. Your supplied tool kit should have winter white caps in it, for when you change air. If you have black caps, don't worry. Your tires take regular year round air. Luckily, that's what mine has. Mojave's and Rubicon's probably take the special seasonal air.

 

[Rusty PW]

It is my understanding that the green caps signify you have summer air in the tires. Your supplied tool kit should have winter white caps in it, for when you change air. If you have black caps, don't worry. Your tires take regular year round air. Luckily, that's what mine has. Mojave's and Rubicon's probably take the special seasonal air.

My JTRD has the black caps. Paid extra for the year round air.

 

[whiteglad]

N2 weighs 14+14 = 28 atomic mass units. O2 weighs 16+16=32. Supposedly the major advantage to nitrogen is its stability vs. more reactive oxygen.

 

[FKN Slayer]

My JTRD has the black caps. Paid extra for the year round air.

My dealer included the black caps if I ordered the max tow package. I had to promise to mention max tow every chance I get though.

 

[IPRoutes]

I pump dry desert air (RH=10) in my Mohave since its "Desert Rated".

 

[jac04]

The whole cap wasn't green on either of mine - like posted above, both of my Overlands came with chromed plastic caps with green tips.
...
Why? Did they come factory that way, or did the dealer do this?

Those are dealer-installed caps.

 

[ShadowsPapa]

Those are dealer-installed caps.

Interesting - both trucks.
Now - why? They come with no caps - or the dealer likes these better? Not a word about nitrogen, no stickers or anything.

If they were yellow would it mean sulfur dioxide?


OK, since "air" is 78% nitrogen and the other parts would be smaller and tend to seep out faster, when your tires are low and you air up again, what you put in is 78% nitrogen.
Does this mean that after 2 years of filling tires when they get low you end up with 97.935% nitrogen?

 

[dcmdon]

This nitrogen fill nonsense will never die. Nitrogen is no better than air.

The reason a nitrogen fill is preferred by some is that because its industrial gas there is zero humidity in it.

It's the lack of humidity that reduces pressure increase.

If you had air from a scuba tank it would be just as good as nitrogen because a scuba compressor has a series of moisture separators that remove all moisture from the air in the tank.

Race teams started using it not because it's special, but because its the cheapest and most available industrial gas. If CO2 was cheaper that is what people would use.

Boyles ideal gas law PV=NRT makes no allowance for the make up of the gas. All gasses expand the same.

N2 weighs 14+14 = 28 atomic mass units. O2 weighs 16+16=32. Supposedly the major advantage to nitrogen is its stability vs. more reactive oxygen.

The atomic mass is irrelevant. Maybe it makes a difference of a couple grams, but that's not enough to matter. And if it is important to you, then you should get a helium fill. Just stay away from Hydrogen even though it's half the weight of Helium. Oh the humanity.

The fact that Oxygen is an oxidizer matters if you are planning to keep your tires for 20 or 30 years. This whole nitrogen fill thing started with race teams, who generally keep tires for just a few days to weeks, maybe months. Besides, the outside of the tire is exposed to deadly Oxygen.

 

[ShadowsPapa]

Just stay away from Hydrogen even though it's half the weight of Helium. Oh the humanity.

Engineers have proven it wasn't the hydrogen that was the issue - it was the coating on the envelope that held the hydrogen. NASA engineer studied it because as an expert in hydrogen fuels, things made no sense. He proved had the envelope not been coated with a substance much like gunpowder, the hydrogen would have quickly burned and been gone - but it was the envelope that burned with such intensity if melted the metal.

It's the lack of humidity that reduces pressure increase.

The early experiments on expansion of gases didn't take into account any humidity in the gases. Once totally dried, they are the same.

 

[Artsifrtsi]

The dealer put nitrogen in mine, so it came with the green plastic caps. The take-offs I bought came with the black plastic caps. I've had two tires patched that picked up nails. I just use regular air to top them off. After 3.5 years, I'm not sure how much nitrogen is left.

I'd say at least 78%...

 

[Ball_Ze]

The dealer put nitrogen in mine, so it came with the green plastic caps. The take-offs I bought came with the black plastic caps. I've had two tires patched that picked up nails. I just use regular air to top them off. After 3.5 years, I'm not sure how much nitrogen is left.

At least 78%. ?

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