[Guest]

Well I searched this section and found some chemistry lessons from SSonic, but that aside I'm wondering what the 'real deal' is here. Chris, must be those glasses...

Sears is now putting dry nitrogen in their tires when you have them mounted. They say its for air pressure stability.

Here is what a Ingersol Rand page says for their $12k machine that does it.

Why Nitrogen?

" Nitrogen is a dry, inert gas used to inflate airplane tires, off-road truck tires, military vehicle tires, and race car tires for improved performance. Oxygen in compressed air permeates through the wall of the tire reducing the tires inflation pressure. During its journey through the tire wall, oxygen oxidizes the rubber compounds in the tire, causing under inflation and deteriorated rubber. Dry nitrogen will prevent auto-ignition, will not corrode rims, and helps the tire to run cooler. "

So... being the anal mod man than I am, whats it gonna take to do this. Rent a nitrogen bottle, regulator etc ?? Or just go to Sears and get my air changed in the tires.

Comments ?

Gerry-

http://auto.howstuffworks.com/question594.htm <<- cool info

 

[Guest]

All Costcos are doing it. I intend to get them to fill my new Khumos in the spring

I usually find that a nice car will cause people to go out of their way at a garage...

 

[Guest]

Gerry,
We do this at the track on the Late Model Race Cars.
It keeps the temp more consistant, but it still changes on those cars, which I dont think would be to much on this car.
Get a bottle from the welding store and a regulator. The hose screws in and a normal coupling with an air chuck and you have the same thing we use, 300 psi fills tires rather quick.

 

[Guest]

Can you mix oxygen with Nitrogen?

I doubt Nitrogen would loose as much PSI when it is cold.

 

[Guest]

Originally posted by GM B Body:
Can you mix oxygen with Nitrogen?

Oxygen and Nitrogen are mixed in a little substance known as air.

 

[Guest]

Haha! durrhh! Im tired.

I guess I was thinking about the air pressure being less stable if a mix of both was added.

 

[Guest]

Well... I've been thinking about coming up with a way to do this. Its apparent there are good reasons for it, and distinct benefits. Are they BIG benefits ?? Guess I need to price out a nitrogen tank and a regulator. I am guessing that the raw pressure in a nitrogen tank is several thousand psi, so a good regulator is going to be needed.

Yep, I'll bet 300 psi will fill a tire pretty quick!

Gerry-

 

[Guest]

Originally posted by CMoney:
</font><blockquote>quote:</font><hr />Originally posted by GM B Body:
Can you mix oxygen with Nitrogen?

Oxygen and Nitrogen are mixed in a little substance known as air.

</font>[/QUOTE]Dammit Chad... I almost spit my coffee all over the screen! TOoo funny!

 

[Guest]

The real reason to do it is that N molecules are bigger, so you get less/slower slow leaks...

 

[Guest]

N2 molicule bigger than an O2 molicule?
Someone explain that one to me.

Karl

 

[Guest]

oops... jason you have awoken the NUKE.

( old navy term for a nuclear power plant operator..... generally smarter than old twidgetts like myself ).

Hi Karl.

 

[Guest]

Hey Gerry, Don't pump me up too much because I have forgotten everything it seems and I have to keep re-learning. I mean it is quite possible a nitrougen gas molicule is "larger" than an oxygen gas but I think maybe jayoldschool is just poking to see if anyone catches that.

Karl

 

[Guest]

PUMP PUMP PUMP

Karl... isn't all that knowledge used to fuel that beast of yours into the 10's ?? Don't under estimate yourself. Really.

NO, NO2, N20.... in a variety of combinations causes everything from an erection, a shrill voice, a laugh or fast passes. But I'm not a chemist. Maybe Chris/SSonic will chime in and set us all straight. Speaking of fast passes....

Besides, I read it on the internet, it has to be true.

Gerry-

 

[Guest]

My opinion : you're spending a lot of time and money for something that is of VERY questionable benefit on anything less than a FULL race car.

There might be a COUPLE of cars (tops) on the forum that go into that category. I don't own one of them, and no one else who has posted on this thread yet does either

 

[Guest]

Ed,

I was just looking at it from a practical side. Sears is doing it to keep their come-back numbers down, and supposedly to keep people from screwing up their brand new tires from incorrect pressures after the first year or so. I'm just interpretting that as meaning more stable pressure with less work over the life of a tire.

I'm sure there is a huge difference on that hot asphalt in a racing environment. I'm just trying to figure out "If Sears and Costco are doing it, why am I not doing it ?"

??

Gerry-

 

[Guest]

Uhhhhh, guys........ hate to burst anyones bubble.... but i believe the atmosphere is 70-75% nitrogen to begin with, and like 20% oxygen and 5% assorted other gasses.... so like... why bother?
And i believe oxygen is a smaller molecule than nitrogen, as i believe molecular weight is less.
I may be wrong on that though

Stu

 

[Guest]

I am not going to do it for performance, I am doing it for maintenance. Everything I have read says that a nitrogen fill is much more resistant to "leak-down" than compressed air. And I find my tire/wheel combo leaks down a lot if the car is sitting. Low profile rubber on chrome aluminum wheels lose air fast when the car sits and the pressure isn't equalized on the beads. I use SmarTire, so I know at every moment exactly what pressure is in each tire.

Unfortunately, everyone has to wait until April for updates from me... I hate winter...

 

[Guest]

Stu,

You are correct. My diving days remind me of the nitrox divers. The air in a 'regular' scuba tank is 79 percent nitrogen, which limits your bottom time under various depths of diving. So they reduce the content of nitrogen to 60/40, calling it nitrox, which allows more bottom time, less decompression time coming back up. ( too much nitrogen in the blood causes the bends )

So yep, we are talking about a 21% difference if you run 100% nitrogen. Doesn't seem like much, but I'm asking for the pratical side. If Sears and Costco are spending the time, money and effort to do this, why ? There must be some real advantage. If its extra mileage out of tires, because the air pressure is more stable over the life of the tire, I'll take some of that. If its more even wear because of constant pressure, that too.

Gerry-

 

[Guest]

Just saw this post. A few comments -

The most important is that this is Dry nitrogen. Air has moisture in it, which will cause corrosion (oxidation) when combined with the 21% oxygen (78% nitrogen) that are the major components of air. When moisture is present it will cause larger changes in the pressure of the tire then dry gas during use since usually some of it exists as liquid and some is in gaseous state exerting a partial pressure depending on temperature. This partial pressure is greater than the pressure increase that could be contributed solely to the change in temperature of the dry gas(es). Any type of dry gas, including dry air, would be beneficial in this regard.

Nitrogen and Oxygen are both diatomic molecules (exist as O2 and N2, two atoms per molecule) and oxygen is actually the bigger of the two, with a molecular weight of approximately 32 Daltons vs. a molecular weight of approximately 28 Daltons for nitrogen, so the part about faster diffusion of oxygen through the rubber tire does not hold water (sic)!

I think dry Helium would be best, it would reduce your unsprung weight!! Too bad it's so expensive!

 

[Guest]

Oh, but He is a very small molecule with molecular weight of 4. It would leak though the rubber tire quickly (think of He ballons)