Nitrogen

[Full_Tilt]

Nitrogen is used because it is inert. It is not affected by atmospheric changes like regular compressed air. Because it is not affected, it can be predicted what tire pressures are going to be for given tire temps.

NASCAR and other major racing leagues use nitrogen because they depend on predictable tire pressures and because they can vary the tire pressure and know it is going to have the desired effect on handling.

That is completely not true. All gasses, be it inert or reactive act exactly the same way when it comes to the relationship between temperature, pressure, and volume (at least at the kind of temperature and pressure were talking about)

If thats what NASCAR says, theyre just dumbing it down.

The real reason is it used is because it doesnt bleed out of the tires as fast as normal air does. This is probably in addition to it being an industrial gas, which means its easily obtained in a clean dry state, even if you could dry compressed air.

 

[TexasKyle]

Uh, atmospheric changes. I.E. the pressure in the tire is not going to change with a change in humidity.

The reason you state is not the reason NASCAR uses it. Also, you are incorrect in saying that all gases react the same to temp, pressure and volume. (which doesnt even make sense really)

It really doesn't matter, in regards to the OP's original question. He does not need to run nitrogen, nor will he gain anything by doing so. That's the point.

 

[Norm Peterson]

The real reason is it used is because it doesnt bleed out of the tires as fast as normal air does.

A psi or so difference over a month or more maybe, but over the short duration of a race, there wouldn't be any meaningful difference.

The dryness issue would matter, otherwise trying to crutch a handling problem with the next set of tires being inflated to a slightly different pressure would be a crap-shoot (at best).


Norm

 

[TexasKyle]

A psi or so difference over a month or more maybe, but over the short duration of a race, there wouldn't be any meaningful difference.

The dryness issue would matter, otherwise trying to crutch a handling problem with the next set of tires being inflated to a slightly different pressure would be a crap-shoot (at best).


Norm

bingo

 

[908ssp]

bingo

So you're saying I was right after all. By the way show me a ready source of dried air. Can't find one? Why there are nitrogen tanks all over the place lets use that its dried. Easy isn't. "inert" to what corrosion? Reacting with the rubber? Like my tire won't dry rot from the outside if I use nitrogen?

Like I said dry air or nitrogen doesn't expand as much as wet air or wet nitrogen if you could find wet nitrogen, it is the moisture in the gas in the tire that makes nitrogen usable for race tires and waste for street tires.

 

[TexasKyle]

So you're saying I was right after all. By the way show me a ready source of dried air. Can't find one? Why there are nitrogen tanks all over the place lets use that its dried. Easy isn't. "inert" to what corrosion? Reacting with the rubber? Like my tire won't dry rot from the outside if I use nitrogen?

Like I said dry air or nitrogen doesn't expand as much as wet air or wet nitrogen if you could find wet nitrogen, it is the moisture in the gas in the tire that makes nitrogen usable for race tires and waste for street tires.

whatever bro. Carry on, carrying on.

 

[frank s]

How much for just the green valve stems?

They're free, but you have to apply for certification from the National Nitrogen Institute.

 

[Full_Tilt]

Uh, atmospheric changes. I.E. the pressure in the tire is not going to change with a change in humidity.

That makes exactly zero sense.

The reason you state is not the reason NASCAR uses it. Also, you are incorrect in saying that all gases react the same to temp, pressure and volume. (which doesnt even make sense really)

It doesnt make sense to you because you apparently dont know anything about gas laws.
All gases unless at very extreme pressure or temperature behave in the same way. Their is a direct relationship between the gases volume, its temperature, and its pressure.
In the case of a tire, the volume is a constant, so just think of it as pressure and temperature. As temperature increases, pressure increases. This relationship between pressure and temperature will be almost exactly the same for all gases. With two diatomic gases, with fairly close molar masses (oxygen and nitrogen) the difference would be extraordinarily difficult to measure. It would never, ever have any noticeable or measurable effect in a cars tire. They will behave identically to each other as far as pressure and temperature are concerned.


As for the speed at which the gases peculates through the rubber. I dont know how long it really takes. I would imagine in a road going vehicle it wouldnt be noticeable but maybe with the constant stretching and deflection of race tires they may bleed pressure off fast enough for nitrogen to help.

They must be doing it for a reason. All I know is that the effect of the tires pressure with atmospheric pressure and temperature changes is not that reason.

 

[Sleeper_08]

From the link above to the Tire Rack site

"And while tires appear solid, if you could see their microscopic structure you would find that rubber looks a bit like strands of cooked spaghetti stuck together. These molecular strands continuously stretch to and from their relaxed state every time the tire rolls and conspire to allow some of the gas to escape through the microscopic spaces between the rubber molecules (called permeation or diffusion). It's been estimated that up to one psi of pressure may escape each month a tire is in service.

............

Nitrogen molecules have a more difficult time escaping through the microscopic spaces that exist between a tire's rubber molecules."