Mixed regular air with the nitrogen in tires

[KJinni]

Having driven a junker my whole life while saving up for my Camaro, I didn't realize that the green caps meant "nitrogen only". So when my tire pressure light came on, I stopped at a station and filled the tires up to 36 PSI (they were initially at 31 before filling). How big of a deal is this? I'm hoping that its not a big deal since the atmosphere is already 78% nitrogen anyways, but I just wanted to be sure and ask you guys. Do I need to purge the tires and fill them up with pure nitrogen or just let it be?

[Indpowr]

Do you have custom wheels or not? If no, I would not worry about it. Nitrogen is good since it has less moisture can help keep the chrome looking good.

[KJinni]

I just have the regular Pirellis that come with the RS package. They're the standard 20". I suppose its not a problem then, thanks!

[mulletman]

You're fine with the "regular" air. Now get rid of those ugly green valve caps.

[6bloodychunks]

we cant put regular air in our tires???

[heRS]

not if you have green valve caps. It means they put nitrogen in your tires instead of air. I googled up a site that sells the nitrogen systems to tire shops, and they have some great sales points for selling nitrogen.
http://www.nitrogentiremachine.com/

and from popular mechanics:

Is Nitrogen Better than Air in Car Tires?
By Mike Allen
Q: Is there any advantage to using nitrogen instead of compressed air in tires? Will I notice improved fuel economy or a smoother ride? Will my tires last longer?

A: Sort of. From the top: Air is 78 percent nitrogen, just under 21 percent oxygen, and the rest is water vapor, CO2 and small concentrations of noble gases such as neon and argon. We can ignore the other gases.

There are several compelling reasons to use pure nitrogen in tires.

First is that nitrogen is less likely to migrate through tire rubber than is oxygen, which means that your tire pressures will remain more stable over the long term. Racers figured out pretty quickly that tires filled with nitrogen rather than air also exhibit less pressure change with temperature swings. That means more consistent inflation pressures during a race as the tires heat up. And when you're tweaking a race car's handling with half-psi changes, that's important.

Passenger cars can also benefit from the more stable pressures. But there's more: Humidity (water) is a Bad Thing to have inside a tire. Water, present as a vapor or even as a liquid in a tire, causes more of a pressure change with temperature swings than dry air does. It also promotes corrosion of the steel or aluminum rim.

If I ever need to top off a tire when I'm out on the road, I'll always briefly depress the tire chuck's valve with my thumbnail and vent some air. If my thumb gets wet, there's water in the line. Some gas stations don't do a very good job of keeping the humidity out of their air system. I don't even like to use a water-based tire-mounting lubricant unless I can let the tire bake in the sun for a couple of hours before I air it up and seat the bead. I've dismounted tires (not mine) that had several quarts of water inside—probably from a compressed-air hose that collected water and was never purged properly.

How is water relevant to a nitrogen discussion? Any system that delivers pure nitrogen is also going to deliver dry nitrogen. Filling tires with nitrogen involves filling and purging several times in succession, serially diluting the concentration of oxygen in the tire. This will also remove any water.

It's certainly simple, although time-consuming, for a tire technician to fill and bleed tires. But most shops use a machine that not only generates almost pure nitrogen by straining the oxygen out of shop-compressed air, but will also automatically go through several purge cycles unattended. Some shops have been charging as much as $30 per tire for this service. I think that's too much. If you're buying a new tire, it should be far less. Still, the nitrogen generator, filling system and technician's time aren't free—the dealer is entitled to some return for that.

So, to answer your specific questions: With nitrogen, your tire pressures will remain more constant, saving you a small amount in fuel and tire-maintenance costs. There will be less moisture inside your tires, meaning less corrosion on your wheels. You will not be able to feel any difference in the ride or handling or braking, unless your tire pressures were seriously out of spec and changing to nitrogen brought them back to the proper numbers.

[PieNsky]

I doubt if you put much "air" into it and it was only about 22 percent oxygen anyway, the rest was nitrogen. That is what normal atmosphere is, give or take.

[spurscar]

Mine didn't come with green caps and nitrogen - is this a state by state kind of thing
based on regulations or something?

[Mr. Wyndham]

Even if you put enough 'regular' air into a constantly sealed tire...eventually it's going to be 99% nitrogen anyways. All the oxygen leaks out over time.

Not a big deal, you'll be fine.

[Elykson]

I had mine changed to nitrogen after I got the car. They don't come that way.

[Spooker_Doodles]

It shouldn't matter. If you are really scared take it to a tire shop and have them change it to nitrogen. Then when you get low take it to a tire shop and have them top you off.

[GhostOutlaw]

The nitrogen compressors they sell arent being entirely truthful.

It's the same device we use to generate oxygen for medical necessity in the home setting. These devices separate the air from the nitrogen. These home concentrators only concentrate, they do NOT purify. The nitrogen systems are the same. The BEST, i mean top of the line, home systems are only about 99%, as per FDA. I somehow doubt the nitrogen concentrators, which function on the same premise, are able to achieve pure dry nitrogen.

Yes, they are delivering N2 to your tire, but they are really only reducing the O2 content.

O2 is a dry gas, just as nitrogen is. O2 is also stable, like nitrogen, under normal conditions (between -100F and 200F, hotter and colder then it gets anywhere on earth).

The air is made up of 21% O2 and the other 78% nitrogen. Leaving 1% for CO2, water vapor and more. These nitrogen concentrator systems do not purge that 1%, it goes into the tire just the same.

Now I know a bit more about gases then I do metals, I'm also going to venture a guess that aluminum doesn't rust, as the article indicates. I think that was one of the cool things about aluminum, but correct me if I am wrong.

On another note, Nitrogen is also the smaller molecule. Meaning that it is equally, if not more, likely to migrate out of the tire just as O2 will. 1-2 lbs per month is what a tire is going to lose, regardless of whether it is N2 or O2.

The biggest advantage to nitrogen is that it is probably changed less by temperature then O2. So stability is a real argument.

And as for that article stating the contents of the air. 78.XX% N2, 20.9X% O2 and the remaining LESS THEN 1% consists of a LOT. Water vapor is actually one of the lower contents there. Somewhere less then 0.4%(on a day where relative humidity is 100%).

[gatorblue camaro]

its not a problem on the camaros but some cars the moisture in the air is hell on the tpms sensors so using nitrogen is a benefit also with the larger molecules the n2 doesnt seep out as fast helping dumb drivers who cant take 5 min out of thier month to check the air pressure in their tires. nitrogen to me is a waste of money you can get your tires filled free at your mechanic if you have ever gotten service there or do so regularly most shops compressors have a dryer on them to get rid of moisture(for air tools)

[Uncle Harvey]

Mine came with the Nitrogen. I did not pay anything extra for it. I am not sure if the dealer did it or if it came from factory this way. My dealer fills it for free.