Nitrogen gas in tires
Race Director
Joined: Jul 2002
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From: Sterling VA
Originally Posted by mwagne16
Better yet, how often do they dry rot from the inside out?
Stop it stop it stop it!!!
Damn this is as old as the hills. You're not racing F1! Forget this already. If it's free, fine. If not, put your cash in your pocket and move on. Supra's were talking about this over 10 years ago. ENOUGH! It was here 6 months ago. Not again. Fill the back with baloons. It will lighten the car.
Stop it stop it stop it!!!
Damn this is as old as the hills. You're not racing F1! Forget this already. If it's free, fine. If not, put your cash in your pocket and move on. Supra's were talking about this over 10 years ago. ENOUGH! It was here 6 months ago. Not again. Fill the back with baloons. It will lighten the car.
You're no fun...
Pro
Joined: Aug 2004
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From: Jacksonville FL
Just had a set of Michelins mounted on a MB M320 at Costco and they said that they use nitrogen because it will not leak as easily as just using "air". I really didn't understand the rationale, but what does a "liberal artist" know. Great price on tires, excellent service, so I trust them, oh well......
Race Director
Joined: Jul 2002
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From: Sterling VA
Originally Posted by ZaydeZ06
Just had a set of Michelins mounted on a MB M320 at Costco and they said that they use nitrogen because it will not leak as easily as just using "air". I really didn't understand the rationale, but what does a "liberal artist" know.
Instructor
Joined: Apr 2005
Posts: 121
Likes: 18
From: MO.
The pressure does not fluctuate like air will. Thats why it is used in the refrigeration industry to leak check equipment lines, if the pressure drops there is a leak, not because the temperature changed.It's also used because its dry no moisture. Its also used in some drag cars so when you would heat up the slicks it will not fluctuate like air would. I wouldmn't pay a extra 50 dollars to put it in a street car. Especially when its only around 12 dollars to refill a cylinder of it.
Race Director
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From: Sterling VA
Originally Posted by xelerator
The pressure does not fluctuate like air will. Thats why it is used in the refrigeration industry to leak check equipment lines, if the pressure drops there is a leak, not because the temperature changed.It's also used because its dry no moisture. Its also used in some drag cars so when you would heat up the slicks it will not fluctuate like air would. I wouldmn't pay a extra 50 dollars to put it in a street car. Especially when its only around 12 dollars to refill a cylinder of it.
Pro
Joined: Aug 2004
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From: Jacksonville FL
Originally Posted by bierbelly
Ideal gas law: PV = nRT. All gases follow this equation at temps and pressures close to ambient. Not until pressures become very high, like 1500+ psig, do compressibility differences between different gases factor into the equation. In a tire, typically inflated to less than 100 psig (probably less than 15 psig in a drag tire), there will be no difference in the pressure fluctuation between air and nitrogen, or between air and helium for that matter.
I'm so confused!!!
Instructor
Joined: Apr 2005
Posts: 121
Likes: 18
From: MO.
Originally Posted by bierbelly
Ideal gas law: PV = nRT. All gases follow this equation at temps and pressures close to ambient. Not until pressures become very high, like 1500+ psig, do compressibility differences between different gases factor into the equation. In a tire, typically inflated to less than 100 psig (probably less than 15 psig in a drag tire), there will be no difference in the pressure fluctuation between air and nitrogen, or between air and helium for that matter.
Racer
Joined: Feb 2005
Posts: 482
Likes: 1
From: Waveland MS
He's pretty much just saying that as temperature goes up, pressure goes up proportionately in a tire. Because both air and nitrogen behave via the natural gas law, they both with have the same pressure at the same temps. Nitrogen is mostly used because it is moisture free (if pure), and inert (it's very good to use as a blanket on a pressure vessel or explosive conveying line, but it has it's own share of hazards around robbing oxygen without any warning smell).
BTW, PV = mRT, where:
P = pressure
V = volume
m = mass
R = gas constant
T = Temperature
For years, us engineers had to sit through this stuff. It would have been a nice change to switch to the liberal arts side and hang with some normal people for a while. A bunch of male enginerds sucking down cans of Jolt and candy bars gets a little old.
BTW, PV = mRT, where:
P = pressure
V = volume
m = mass
R = gas constant
T = Temperature
For years, us engineers had to sit through this stuff. It would have been a nice change to switch to the liberal arts side and hang with some normal people for a while. A bunch of male enginerds sucking down cans of Jolt and candy bars gets a little old.
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Drifting
Joined: May 2003
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From: Greenwood SC
Originally Posted by ZaydeZ06
Just had a set of Michelins mounted on a MB M320 at Costco and they said that they use nitrogen because it will not leak as easily as just using "air". I really didn't understand the rationale, but what does a "liberal artist" know. Great price on tires, excellent service, so I trust them, oh well......
Just the opposite.
A Nitrogen atom is much smaller than an Oxygen ( O2 ) molecule. Leak testing of pipes and tanks in many industrial applications is done using Nitrogen due to the fact that it will leak through a smaller hole!
Le Mans Master
Joined: Sep 2003
Posts: 8,847
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From: Longview Texas
Originally Posted by bierbelly
On the other hand, one of the things air does for tires (besides inflate them) is to help remove the heat from the rubber; for example, if you run a tire low on air, it can fail because it overheats due to insufficient air volume to absorb the heat. ! 
I think that underinflated tires overheat because the sidewall of a low tire flexes more and thereby generates more heat. Not because there is less air to remove the heat.
Besides, if the air absorbs the heat, the heat has to go somewhere, which eventually is back into the tire or the wheel.
Race Director
Joined: Jul 2002
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From: Sterling VA
Originally Posted by TEXHAWK0
Don't think so....
I think that underinflated tires overheat because the sidewall of a low tire flexes more and thereby generates more heat. Not because there is less air to remove the heat.
Besides, if the air absorbs the heat, the heat has to go somewhere, which eventually is back into the tire or the wheel.
I think that underinflated tires overheat because the sidewall of a low tire flexes more and thereby generates more heat. Not because there is less air to remove the heat.
Besides, if the air absorbs the heat, the heat has to go somewhere, which eventually is back into the tire or the wheel.
Team Owner
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From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
Originally Posted by bierbelly
It may have something to do with the fact that air compressors condense moisture in the compressed air. A lot is usually knocked out with a trap, but some still exists. At high altitude, obviously it'll further condense and freeze. Compressed nitrogen from liquid N2 is very dry, powers of ten less moisture than compressed air. I don't know why the presence of a little ice inside the tires would cause a problem.
Or maybe the military has been sold a bill of goods too. After all, they buy $400 toilet seats...
Or maybe the military has been sold a bill of goods too. After all, they buy $400 toilet seats...
Nitrogen's inability to support fire, as well as it's extremely low moisture content (eeexcellent for electronics!), is the reason we always kept our submarine missle tubes pressurized with the stuff at sea (about 3 or 4 psi as I recall). That's a lot of nitrogen since the tubes measured roughy 6ft x 36ft.
I agree with the others here; it's the lack of moisture which leads to greater pressure stability and if it were available everywhere for a very low cost, I would gladly use it.
Race Director
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From: Sterling VA
Originally Posted by Sandra Bigwoode
Wrong, you forget the whole reason for the excercise is to get rid of the water vapor suspended in 'air' in the tire which is a very 'un-ideal' gas and expands a great deal when heated thus raising tire pressures to unacceptable levels in race tires.
It isn't all that important on cars driven on the street unless you run at high speed for a long time on a hot day...
It isn't all that important on cars driven on the street unless you run at high speed for a long time on a hot day...
But then, we weren't talking about water, we were talking about air. Of course a dry gas, whatever it is, will be better than a wet gas, but even the amount of moisture in pumped compressed air w/o a moisture knockout won't have much moisture in it. They'd have to take the outlet off the bottom of the tank to get enough water into the system to make a difference.
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From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
Originally Posted by bierbelly
Uh, wrong. Water vapor won't expand any more than any other gas. OTOH, if LIQUID water is in the tire, it will expand into a much larger volume of water vapor, if it reaches a high enough temp to vaporize. Once vaporized, it's gonna act like an ideal gas.
But then, we weren't talking about water, we were talking about air. Of course a dry gas, whatever it is, will be better than a wet gas, but even the amount of moisture in pumped compressed air w/o a moisture knockout won't have much moisture in it. They'd have to take the outlet off the bottom of the tank to get enough water into the system to make a difference.
But then, we weren't talking about water, we were talking about air. Of course a dry gas, whatever it is, will be better than a wet gas, but even the amount of moisture in pumped compressed air w/o a moisture knockout won't have much moisture in it. They'd have to take the outlet off the bottom of the tank to get enough water into the system to make a difference.
Man I can tell you don't live in Houston. The relative humidity is so high here, I can almost grab a hand full of air and squeeze the water out of it. Shop compressors here are notorious for moisture content, especially those that are out in front at a gas station. How many times have I seen the presence of water in an air chuck when I press the valve in? Hmmmm, I'm thinking hundreds here. 
Dry is good. 
Race Director
Joined: Jul 2002
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From: Sterling VA
Originally Posted by LoneStarFRC
Dry is good.
I never disputed that. If you want to purchase it, dry air is available in cylinders too. The military/aviation use to avoid the oxygen content for safety purposes makes sense, but in a car? Way overboard.
Houston Texas, what is that?
