Ron

Does anyone use nitrogen for their street tires?

I ask because I just got a new set of tires for my SUV and thats what they fill them with. They say it will maintain a more constant pressure with changes in temperature, i.e., ambient temperature that is. Is that correct?

Apparently all Costco stores now fill tires with nitrogen.

TheOtherEric

It's a gimmick. There's only a little bit of truth to the position that nitrogen will hold pressure better. Heck, air is already 80% nitrogen anyways. For street use, it's beyond silly.

kkim

Yeah, I kinda scratched my head when the GF bought tires at Costco and it came with those green valve caps to indicate there was nitrogen inside. I suspect, as Eric said... it's a gimmick.

I mean, if it really makes that much of a difference, what happens when you need to fill your tires and you only have regular, lowly air to put in there? Oh wait.. when will Costco start selling bottled nitrogen?

Mark in Baltimore

For a street car, nitrogen's benefits seem minimal. For a race car, the benefits are cause for controversy and discussion. Try searching under "tire" and "nitrogen" on the GT2/GT3 board. There was a thread a couple of months ago that discussed this issue.

grmnxtc

So, to add to the "sillyness" of this gimmick, do they vaccuum evacuate the air that's already in the tire when it's mounted and then refill with nitrogen? I think not.

Costco equivalent of snake oil.

Perhaps we should fill with Helium and get a little weight loss..... hmmmm....

graham_mitchell

Funny that this thread should come up. I was going to look into this myself, just out of curiosity, after a close encounter with an aircraft last week in which I noticed that the aircraft tires were labelled as inflated with nitrogen. I assume that nitrogen expands less with increased temperature. I'll go check out the archives now.

texas911

Costco does it for free so I don't see how its a snake oil. If they charged extra then yea, but I think they are just doing it for the benefit of their members.

97Targa

Isn't nitrogen dryer than "plain old air"?

993RS

I use nitrogen for my Pirelli Zero Corsas. Offered by my tireshop.

dhicks

hahahaha helium, very funny grmnxtc....but would that make them sound funny too?

Greg H.

The cynic in me says that Costco does it so that you come back there regularly for tire maintenance since you can't get the nitrogen anywhere else. While they are servicing your tires, you can wait inside...

Greg H.

993RS

the tire maintenance in my case is free.

Bob Rouleau

The theoy behind nitrogen is that it contains less water (humidity) than compressed air. The dryness is what makes it more stable over temperature. Some also say thast nitrogen molecules are larger than air and do not leak through the very thin rubber of racing tires as easily. Grmxptc (sic) correctly points out that to derive full advantage of the dryness of nitrogen, the tire have to be properly purged of all the humid air.

Rgds,

kary993

Yes, this is absolutely correct.

Most of us that have regular air compressors can try putting out some air on the floor and will notice that water will build up as you continue to spray the air on the floor. In fact most compressors have a valve on the bottom to drain the water tha builds up in the tank.

Nitrogen will not have this problem. There also have been many discussions about CO2. Some folks believe that CO2 has more water in it that "air", but in reality, tested at a race track I found tire temps and pressures to be almost identicial (within 1.2 of a pound). Though I did not purge the air from the tire my testing might be a bit flawed as well, but close enough for this amateur. For nitrogen to be effective, you do need to purge the air out of the wheel/tire and replace with nitrogen which is not all that easy to do well and takes some equipement that most of use do not have.

The topic of molecule size is another very shady discussion. Most tire manufacturers, (one of which I just got off the phone with, Toyo), suggest that a tire will loose about 1 pound of pressure of a 1 to a month and half through the bead. I asked if this was dependent upon the gas in the tire and they said it really did not matter as air, nitrogen and CO2 are roughly the same molecular size (not structure).

So is Costco selling snake oil? Maybe not since they are not charging, but for all practical purposes it does nothing for the street driver. BTW, what are the Costco customers to do when their tires loose some air? Drive back to costco to get the tires filled properly? Stop at the local gas station and ask for nitrogen please? What a joke all that is!!!

Laura

Race teams do evacuate and refill tires with dry nitrogen to achieve below 10% relative humidity. It's not the type of gas , it is the relative humidity of the air be it Co2, nitrogen.... The predictability of expansion is what you are concerned with.