Filling tires with nitrogen?

  • Thread starter Thread starter Carlos_23
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Have you heard about this before?

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Carlos_23

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Hello all. My dad and I were talking some time ago about this, because he read in a magazine (Popular Mechanics, probably) that it was better to fill tires with pure nitrogen rather than compressed air.

I just wanted to ask some questions:
Have you tried this?
Does it need special equipment?
Does it have any advantages/disadvantages over normal air? (I already searched through Google, just wanted to read some comments about this. Also, I guess this is the right forum to ask, if it isn't, please move/delete it.)
 
I've never done it (never felt the need to), but I know it's common practice in top-level motorsport. F1 tyres are filled with nitrogen, for example. I couldn't tell you why exactly it's done though, but I believe it'll be something to do with the fact that nitrogen is more stable than oxygen.
 
Nitrogen is "thicker" than normal air therefore it won't leak out as much. Nitrogen also stays at more of a constant tempertaure, compared to normal air which fluctuates alot when in a moving tire.
I have checked the pressure in people's tires before when I worked at a "Discounting" Tire Store, and three of the tires would be 30psi, and the other one would be at 80psi! And the customer said they haven't touch the tire pressure in months.
 
Basically Nitrogen is less reactive so when it is heated it doesn't expand as much as Oxygen, preventing tyre pressure from increasing and possibly causing blowouts.
 
What would happen in a high speed blowout?
 
I imagined it would have a wacky racers-esque effect where nitrogen rushed out of the tyres propelling the car forward.

Peter Perfect hasn't failed me before now...
 
Unless your tyres are running eally high temperature, or your brake discs are hot and paticulary close I don't think there is much of a difference.
 
While your tyres might get hot, I doubt your disks get that hot.

Seriousley though, you are travelling pretty fast but I can't see that and your weight transfer getting your brakes F1 hot.
 
nitrogen has bigger molecules than air, so it leaks less
its an inert, dry gas. becasue it has no water vapor in it, its pressure doesnt rise as the tire tmeperature rises. this is supposed to yield gains in longevity, ride comfort etc as the air pressure will be what the engineers designed it to be.

air is about 79% nitrogen
 
ExigeExcel
While your tyres might get hot, I doubt your disks get that hot.

Seriousley though, you are travelling pretty fast but I can't see that and your weight transfer getting your brakes F1 hot.
Click to expand...


Of course no F1 hot haha. However the Brembos do get pretty damn warm.
 
neanderthal
nitrogen has bigger molecules than air, so it leaks less
its an inert, dry gas. becasue it has no water vapor in it, its pressure doesnt rise as the tire tmeperature rises. this is supposed to yield gains in longevity, ride comfort etc as the air pressure will be what the engineers designed it to be.

air is about 79% nitrogen
Click to expand...

I've got Nitro, and my tires have stayed stiff for over a month now. Previously, due to the heat around here, I'd lose about 1-2 psi per week.

I'm thinking of deflating them actually... never realized how stiff my air pressures were before, as I'd always lose that stiffness within a few days of pumping.
 
Nitrogen actually has smaller molecules than oxygen. N2 has an atomic mass of about 28 for the two atoms, O2 has a mass of 32. But the amount of diffusion through the tyre is tiny, as tyres are designed not to do this. Any that does go on is more likely to favour the smaller N2 molecule.

The reason Nitrogen is used is that it is portable, you have a big bottle instead of a compressor, and and industrial compressed gas is usually dried, so there will be little water vapour in the tyres.

As it warms with your tyres it will expand and the pressure will increase. This will also happen with air. There is not really any technical benefit to using N2, just the ease of use.

thanks,

Kurtis.
 
neanderthal
so racers and formula 1 and co dont know what they're doing? here's you hat :dunce:
Click to expand...

Quiet, you ignominious ****.


Racing teams use nitrogen to fill their tires because:
- it's cheaper and faster to purchase and use compressed nitrogen
- using one pure substance increases the repeatability of testing (you know exactly what's in the tires, whereas the content of air fluctuates (relatively) wildly)


Members of the general populace might as well skip the nitrogen fill unless it's free.
 
Repeat--Air is mostly nitrogen anyway. Someone mentioned that nitrogen would come in a bottle, instead of a compressor. So, think about it this way. You buy Nitrogen, you get pure nitrogen (pure gas) in a bottle. On a humid day, you still have pure gas.

With a compressor, you get a lot of water vapor. Have any of you guys ever worked construction? Most air compressors have a blow off valve underneath to drain all the water that builds up in the compressor tank. So, you're basically putting that same water rich air in your tires, and it too can conceivably condense inside your tires. And a little water sloshing around inside their wheels is probably the last thing any F1 driver needs, adding mass and throwing balance off.
 
Firebird and skicrush are bang on. at the temperatures and pressures involved in tyres most gases will respond almost identically to changes constrained by the ideal gas law PV=nRT.

Nitrogen is useful as it is dry, consistent, and doesn't need a compressor requiring fuel or a power supply.

I've heard stuff about tyres running cooler with N2. I can't think of why this would be, any ideas?


cheers,


Kurtis.
 
The only thing I can come up with is again related to the humidity--I imagine the water vaper will make the gas more dense, and probably more thermally conductive.

Plus, you can see where it would be impossible to ideally pressurize a tire with any kind of liquid water in it--as the tire heats up, the water vaporizes, and the pressure goes up (significantly more than just due to the other expanding gases).
 
By the way, I've seen street cars get their brakes VERY hot. One incidence of a 350Z having bright orange rotors after a single run stands out in my mind.
 

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