tires with Nitrogen

[blacksheep4x4]

ViperQA1 is correct. That is exactly why the Navy uses it too.



Deployed USS Abraham Lincoln (CVN-72)

I second this. There is a reason the military fills thier aicraft tires with nitrogen. (Crew Chief Montana Air Gaurd).

 

[RustyJC]

The following is from HowStuffWorks.com:

Nitrogen Instead of Air

Most of the (NASCAR) teams remove the air from the tires and replace it with nitrogen. Compressed nitrogen contains less moisture than compressed air. When the tire heats up, moisture in the tire vaporizes and expands, causing the pressure inside the tire to increase. Even small changes in tire pressure can noticeably affect the handling of the car. By using nitrogen instead of air, the teams have more control over how much the pressure will increase when the tires heat up.

Rusty

 

[fkovalski]

OK, OK- I am convinced that nitrogen is better than justy plain ole air... .

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.

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... . can any one recommend which brand of nitrogen to use... No wars please :-laf

 

[cosborne]

More "fun" reading... .



http://www.n2revolution.com/



http://www.getnitrogen.org/



http://forums.scotsnewsletter.com/lofiversion/index.php/t9369-0.html

 

[rbattelle]

The following is from HowStuffWorks.com:

Rusty

The gas constant for water vapor is 85. 73 ft*lbf/lbm R, or 61% higher than dry nitrogen. So it makes sense that you'd want to keep water vapor out of your tires.



So why not just use dry air? There aren't really any arguments between nitrogen and dry air, considering the extra cost associated with isolating and compressing the nitrogen, and the associated logistics (unless lack of oxidizer is part of the requirements).



-Ryan

 

[WSnyder]

I don't think the race teams started using nitrogen for any performance gains. They started using it for convenience. No more compressors or the huge generators to run them nor did the track need to provide extra power to run the compressors or provide any air for the teams. The teams just show up at the track and the local specialty gas provider has already delivered a truck full of nitrogen cylinders ready to go. The team pays for the tank full of gas, attaches their regulator and away they go, no fuss, no muss. The pits are quieter and less crowded with no compressors around and the tank runs all of the air tools along with any tire needs. Tanks easily mount to the pit kart for a portable source. The off road guys use the liquid CO2 tanks for some of the same reasons. I think there is some urban legend to all of this and we the public inflate what we perceive the racers do as being some big performance gain when the actual gains may be minimal and we've just missed the real reason why something was done in the first place.

 

[george]

Got the nitrogen on board now, went by Costco this morning and had them fill the truck tires then I went home and got the 5er and had its tires filled too.

 

[azpete]

I am not expert on this but here is my two cents. When I was a splicer for the phone company, the large copper wire cables where paper insulated. We carried two 2400psi nitrogen tanks on our trucks. Any time we opened a splice it had to be buffered with the nitro tanks. Moisture, paper, copper and electricity do not go together. Nitrogen is just dry air. An air compressor can have alot of water content in it which is pushed into the tire. Add alot of heat and the pressure inside the tire will rise because of the moisture content. In a race tire that creates alot of heat you don't want to have a one to what ever psi change in tire pressure. Nitrogen being a dry air will not have the pressure change at different temps. That's why the manufacturers say the pressure on a cold tire because they know how much it will rise on a hot tire.

 

[betterthanstock]

Got the nitrogen on board now, went by Costco this morning and had them fill the truck tires then I went home and got the 5er and had its tires filled too.

Why not helium? You could load it a little more and still be road-legal.

 

[george]

Why not helium? You could load it a little more and still be road-legal.

Its my truck and I do what I want with it, anybody doesn't like it can add their name to the long list of people that can basically kiss my *****

 

[JasonBrown]

I can see the point, I am sure many of us are launching our trucks up to 20,000 feet.

 

[Eric_77]

I don't know of any longevity benefits, but Nitrogen is used in the roadracing world, and most of my experience dealing with that is from the motorcycle side. The primary benefit, and only one I can remember right now, is temperature resistance, i. e. , the pressure you set is the pressure you will have once the tire is up to temp, which can be a big issue w/ the handling of a motorcycle. That's the only benefit I can see. But if people are willing to pay $5 per tire for nitrogen for their tires, more power to 'em. I'm opening a nitrogen station.



I really see no benefit on the street.

Hey scootergmc what do you race? Who with?

FYI I am Eric Kelcher w/CCS

 

[brods]

The gas constant for water vapor is 85. 73 ft*lbf/lbm R, or 61% higher than dry nitrogen. So it makes sense that you'd want to keep water vapor out of your tires.



So why not just use dry air? There aren't really any arguments between nitrogen and dry air, considering the extra cost associated with isolating and compressing the nitrogen, and the associated logistics (unless lack of oxidizer is part of the requirements).



-Ryan

Agreed, but how many people have any control over the moisture content in the air they get? I believe some of the tire balancing powder people offer a moisture blocker to connect between the tire valve and the compressed air source, but how many people will go to the trouble to buy and use such a device? Also, if regular air does leak out at a faster rate, nitrogen may have an advantage for those who do not do regular (or any) pressure checks. Judging from all the severely under inflated tires you can see on the roads, maybe tire shops using nitro is a good thing. (You'll never catch me paying extra for it though)

 

[JOblenes]

The gas constant for water vapor is 85. 73 ft*lbf/lbm R, or 61% higher than dry nitrogen. So it makes sense that you'd want to keep water vapor out of your tires.



So why not just use dry air? There aren't really any arguments between nitrogen and dry air, considering the extra cost associated with isolating and compressing the nitrogen, and the associated logistics (unless lack of oxidizer is part of the requirements).



-Ryan

Ryan, we are obviously on the same page in regards to the purely thermodynamic impact of nitrogen, but get this. I phoned my local industrial gas supplier (Praxair) to inquire about the relative pricing of bottled gases and for 99. 98% pure nitrogen it was $CAN 82. 68/cylinder and for "dry" air it was $CAN 96. 20/cylinder. I asked him to recheck and in fact their price for nitrogen was cheaper, go figure. Obviously I would never consider filling my tires from any bottled gases (simply too expensive), but I am sure I could achieve almost the same effect with a simple dessicator on my home air compressor (like the ones use before paint guns) not that I would actually go to that trouble either.



Jonathan

 

[rbattelle]

I phoned my local industrial gas supplier (Praxair) to inquire about the relative pricing of bottled gases and for 99. 98% pure nitrogen it was $CAN 82. 68/cylinder and for "dry" air it was $CAN 96. 20/cylinder.

Wow, that is weird wild stuff. So bottled N2 is cheaper, yet some tire shops actually charge $5/tire for it!? Yikes. That's a business I need to get into.



-Ryan

 

[MChildress]

As said above the biggest plus of a 2200 psi nitrogen tank at the track is portability and not having to fool around with compressors. The benifits in tires are positive but minimal. Webster Dictionary (air 78% nitrogen,21% oxygen).

 

[JThiessen]

Its not just the moisture content of the air from the compressor. Just the heating and cooling of the air inside the tire will produce water. Thats the biggest benefit. A simple filter on the compressor would take 99% of the moisture out of the air from the compressor.

 

[DPeltonen]

This thread is why it is such a great idea to check with a "reputable authority" before you believe what you read in a public forum.



As far as why aircraft use nitrogen... It's required by law!



“PART 25--AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES 25. 733 (e) For an airplane with a maximum certificated takeoff weight of more than 75,000 pounds, tires mounted on braked wheels must be inflated with dry nitrogen or other gases shown to be inert so that the gas mixture in the tire does not contain oxygen in excess of 5 percent by volume, unless it can be shown that the tire liner material will not produce a volatile gas when heated or that means are provided to prevent tire temperatures from reaching unsafe levels. ”



With respect to the the stability issue; it is not an issue. At relatively low pressures (ie tire pressures) N2, O2 and water vapor will all behave as ideal gases, and follow PV=nRT. Pressure will increase or decrease to the same extent as the temperature increases or decreases regardless of which gas is in the tire. (Even at 300 psi, which is about 20 atm, there is little deviation from ideality. ) Therefore the comments about N2 not changing in pressure as the temperature changes are without merit.



In addition, every gas is going to escape from a tire, regardless, as long as the pressure inside the tire is greater than the pressure outside the tire. The gas molecules are going to diffuse through the walls of the tire at a very slow rate. It doesn’t make any difference what the gas is, although there are small differences between the diffusion rates of oxygen and nitrogen. Since nitrogen is slightly less massive than oxygen (28 g/mol vs 32 g/mol) Graham’s law predicts that nitrogen will diffuse slightly more rapidly than oxygen.



Nitrogen in the tires enhances your tire longevity and ride as much as that magnet on your fuel line increases fuel mileage... ..... that's why I always use synthetic blinker fluid. It allows the tornado attachment on my intake to last 30% longer.

 

[Alphacowboy]

i find this all very funny as... . who uses a vacuum and sucks all the "AIR" out of a tire first, then puts in 100% nitrogen? :-laf



The simple fact is that when mounting a tire, you get the atmospheric air in the tire before even inflating it. so there is going to be moisture and O2 in the tire no matter what you fill it with after the bead is set. There is NO way to get 100% nitrogen in your tire. Even though the 02 and moisture levels will be lower, I dont see how its going to make that big of difference.



Nitrogen is used in race car tires because yes, it does tend to expand a little less, but the main thing is convienece. When I worked on a race team, we used nitrogen so we didnt have to carry around a compressor.

 

[george]

WHO CARES? If you don't like the idea don't put it in your tires, it's as simple as that.