I had some tire work done at Costco last Saturday and they filled my tires with Nitrogen. They swear by it. Says it is way more stable than just regular old air. Anybody using nitrogen in their tires? Is there a noticable difference? Eddy

Air is 78% nitrogen.

Sounds to me as if somebody at Costco is pulling on your leg............

I have heard that the big benefit is no water. Which means no rust on steel wheels. I have also heard stories about tire shops that don't drain their compressors, and their first few customers in the morning get lots of water in their tires. Dunno if there's any truth to that. Costco claims improved gas mileage and safety.. they may be, but I doubt it's measurable.. unless you take the large amount of water worst case.

Costco claims the air we breath is 78% Nitrogen and 21% Oxygen. The 21% is what expands and contracts due to the moisture content and temperature changes. Also, the oxygen is what leaks out of our tires in 6 months. I was just wondering if they were just blowing smoke up my

I believe there is a value to nitrogen. I don't think it's necessary for street cars, but it doesn't hurt.

well here is a thought... is it cheaper to have a company drop off n2 bottles than to purchase, wire, and maintain a compressor. when i played paintball n2 was just coming out and we could get 1800 psi n2 bottles for like 6 bucks, and thats was for a 200 cubic foot bottle. how many tires can you fill from a 200 cubic foot bottle. lets say about 50, so its about 12 cents a tire, not very expensive.

This is a standard practice in Europe done for saftey and its convienient to not always have to check the tire pressure because of big temp changes (Summer-Winter), and 100% required in Aviation (Aircraft Tires). The main reason for it is the stability of Nitro during temperature change, the pressure remains more constant. Remember that these tires see a temprature range that is so wide that use of a stable gas that is little affected by temp is a must. -50 to + 300 F caused by temps at 35000 ft, then after landing, and stopping something that weighs 500,000 pounds the brakes get a little warm. The heat shields on the wheels help, but allot of heat goes straight to the tires...

Some benefits:

Nitrogen permeates through the tire 3 to 4 times slower than oxygen - tires maintain pressure longer for better fuel economy, better tire life, and increased safety.

Nitrogen reduces oxidation to tire rubber and rims caused by oxygen in standard compressed air.

Nitrogen filled tires run about 20% cooler than tires filled with standard compressed air - tires last longer.

I bought tires at Costco a few months ago, they replaced the valve caps w/ green colored ones to indicate nitrogen.

Was wondering if those green dots painted on some Porsche wheels means they were filled w/ nitrogen from the factory.

So THAT'S what the green cap thing is about.. I'd been wondering.

I figure if oxygen leaks out so much easier, and I top off my tires every few months, they should end up nearly pure nitrogen

QUOTE (McMark @ Mar 21 2005, 09:41 PM)

Some benefits: Nitrogen permeates through the tire 3 to 4 times slower than oxygen - tires maintain pressure longer for better fuel economy, better tire life, and increased safety. Nitrogen reduces oxidation to tire rubber and rims caused by oxygen in standard compressed air. Nitrogen filled tires run about 20% cooler than tires filled with standard compressed air - tires last longer.

Yep...McMark pretty well covered it.

Another reason aircraft use "dry-nitrogen" is because at cruising altitudes it's friggin' cold (technically speaking), and if they used compressed air the moisture would condense and then freeze. A chunk of ice in your tire would throw off the balance of the tire upon landing..........not good!


(URY914's probably thinking...... "If I used helium, my car would be even lighter!!")

very intresting

One of the guys I raced with in SCCA always brought a tank of Nitrogen to the track. My tire pressures would go up 6 - 8 lbs. in a 20 min. session with regular air. His would only go up 2 - 3 lbs with nitrogen in his tires.

I think I read somewhere that they use dry-nitrogen in F1 cars just for that reason (lower expansion)

My buddy had a couple huge tanks of nitrogen in his race car trailer. Used it in his tires but mainly, it ran the built in jacks in the racecar.

The jacks needed like 250 psi to work, so an air compressor was out of the question.

He also used it to power a giant impact wrench used for the centerlock nut on the wheels. That big nut needed like 350 lbs of torque.

The magic word is dry nitrogen. Air has a lot of moisture in it. Using nitrogen in your tires you will not have the same rate of expansion you would with air. On track tires add 2-3# pounds to your starting cold pressures from when you were using air. Gives the tire a better footprint when starting out. When using air it is fairly normal to have a 7-9# difference between cold and hot pressures, with nitrogen it's usually 4-5#.

I have had my Costco tires now for about 6 months filled with the Nitro. Wow what a difference!!! fantastic gas mileage! Incredible grip!





not.....

sux if you need a tire fixed and you are not near a costco... I don't think most tire places Keep nitrogen...

yep, so now I carry a bottle of NOS in the front trunk to fill the tires!

The spare is hooked by the window washer tube to my super secret NOS spray setup for extra hp. No one can figure out why I beat them street racing!

Geoff

QUOTE (tat2dphreak @ Mar 22 2005, 06:55 AM)

sux if you need a tire fixed and you are not near a costco... I don't think most tire places Keep nitrogen...

I see signs advertising nitrogen for tires at nearly all the mainline tire stores around here, and we are, relatively speaking, out in the sticks. BTW, when I worked in LA in the 70s, we used it in all our customers' time trial cars. The Cap'n

About draining the air tank: I went to fill a tire at a service
station and all I could get was water spray.

I went somewhere else.

KT

I don't know why O2 would escape faster than N2, the O2 is a bigger molecule. The oxidation of the rubber is much more important on the outside where you can't get away from it. Not to mention the UV rays. The only important difference is the bottled Nitrogen is dry, no other factor is important.

[QUOTE]I don't know why O2 would escape faster than N2, the O2 is a bigger molecule[QUOTE]

I think O2 is a smaller molecule than N2, that is why the tires deflate after 6 months. Any chemistry majors here? Eddy

The element nitrogen is number 7 (7 protons) and oxygen is number 8 (8 protons). But since we're talking molecules made of two atoms of each, it would depend on how close they are together (I think).

QUOTE (smooth_eddy @ Mar 22 2005, 05:52 PM)

[QUOTE]I don't know why O2 would escape faster than N2, the O2 is a bigger molecule[QUOTE] I think O2 is a smaller molecule than N2, that is why the tires deflate after 6 months. Any chemistry majors here? Eddy

Don't know about a chemistry major, but I am a physicist. There isn't a great difference in the size of the two molecules. If you want a real leak then try helium.

Got Costco tires for my six about 2 weeks ago. They put in nitrogen. Could not figure why the gaudy green valve caps. Replaced 'em with black as soon as I got home. Learn something new on this board every day......green=nitrogen.