Nitrogen in corvette tires, good or bad?

[junkyardjohn]

Pros / cons of use of nitrogen in run flat c6 tires. Do they sell a nitrogen compressor? Or is it a storage tank that gets filled when needed.

[Tuna]

My Caddy dealer keeps putting nitrogen in my CTS-V's tires when they service it. Makes no difference to me.

Nitrogen isn't a wet gas like 'air' is - i.e. no or very little humidity in nitrogen - so nitrogen doesn't expand as much when heated like air does. That means the pressure doesn't go up as much in the tires while you're driving. That's supposed to make a big difference in the way the car feels and in tire wear.

With the stiff side walls of run flat tires, I can't see a couple of psi making much difference in the way the car feels and I haven't seen any difference in tire wear. Maybe nitrogen makes more difference in regular tires than it does in run flats. I just don't know though.

As for being bad in the tires - definitely not.
As for being better that air - I just can't say - yet.

Nitrogen costs you more money and if you want to service your own tires, you'll need to buy nitrogen bottles and keep them around when you need more pressure.

[jrose7004]

I put some new Firestones on my F-150 Supercrew and the tire dealer put it in there. I think it's smoke and mirrors but he put it in for free.

[Vettehead Mikey]

Nitrogen in tires is the single biggest, most misunderstood scam in automobiles today.

The difference in coefficient of expansion of air (78% nitrogen) vs. typical tire nitrogen (~90%) is so small it is almost impossible to measure. If there were a large difference, then inflating the tires when cold to the recommended pressure would mean that they would be running UNDER inflated on the highway.

Simple example of how this is marketing mumbo jumbo and NOT technically substantiated.

If it's free, sure why not, it you have to pay, forget it.

[Rex S]

Mercedes Benz and BMW strictly forbid it in their cars. Take it for what it's worth. I know some of each dealers insist on using it but the factories say no.

[Blue260]

I'm the guy you'd sell a bridge too!

When I had my C5 I purchased a new set of tires from my Chevy dealer. They raved about a nitrogen fill and touted how the Chevy race team even uses it.

They went on to say how nitrogen had larger molecules then air which would prevent any air seeping out from the rim. They also mentioned how tire tread wear would be increased because nitrogen doesn't heat up like air and doesn't contain any moisture. It sounded too good to be true, so like the gullible person I can sometimes be (I like to believe the best in people) I purchased it for $40.00.

Those claims may be true about the chemical properties of nitrogen, but in real world application it's nonsense.

I did not see any cooler temps on my tires when driving - they were the same as air. I didn't see any extended life on my tires, they were the same 15-20k life as with most GYRF's. And, I wasn't able to see any benefit of a constant 30 lb. tire pressure. In fact, I had to add air every couple of weeks to maintain correct tire pressure. And, in doing so, I no longer had a 100% fill.

Maybe I can sell you the bridge I bought!
chris

[Vettehead Mikey]

They went on to say how nitrogen had larger molecules then air which would prevent any air seeping out from the rim.

This another angle of the scam/myth. If the nitrogen molecules were larger and therefore didn't escape, a tire filled with 'regular air' would eventually become filled with pure nitrogen all on it's own. The tire walls would act like a filter and let only oxygen molecules through.

Funny how the scam artists don't have answers for this and the other points above.

[LLC5]

Not much benefit on a street driven vehicle, too many variables. It won't hurt anything either, other than your pocketbook if you pay money for it.

[Red Vette]

To answer your question about the nitrogen compressor, I have seen two types at the tire dealers. The first was a compressor that removed the oxygen from the ambient air, then was transferred to the tires. However, the dealer's compressor did not have an evacuation system to remove the air from the tire. Just removed the valves and let the tires go flat, leaving ambient air in the tire before it was filled with the nitrogen from the compressor. So the tire was filled with nitrogen that mixed with the residual oxygen in the tire. The second was a compressor that removed the oxygen from the air prior to filling the tire. This compressor also had the system to purge the tire prior to adding the nitrogen thus eliminating the residual oxygen left in the tire. I had both 02 corvettes filled with the second compressor system this spring when I purchased new tires, no charge. I had the 94 corvette tires (has a new owner now) filled with nitrogen from the first type compressor, including the spare. The spare did not lose any pressure over the 6 month storage period. The 4 tires on the ground on the 94 lost about 2 psi over the storage period. Had to pay $20 for the 94 for the 5 tires, but fee was for the life of the tires. Get free fillups with both systems, but only from the original dealer. I won't purchase nitrogen for my tires, but will take it when there is no charge when it comes from the second type compressor system. I have a standard air compressor, so I can fill my tires when they lose pressure. If you are wondering if a car has nitrogen in the tire, look at the valve caps, they are usually green. BTW, for run flat tires, there is a special metal green cap that continues to send the pressure signal to the DIC. For non run flats, there is a green metal cap that is different than the run flat cap. In my opinion, the plastic green cap only looks good on the spare when it is in it's storage compartment.
Barrett

[KANE]

...If it's free, sure why not, it you have to pay, forget it.

I've thought the same thing.

[Tuna]

If you are wondering if a car has nitrogen in the tire, look at the valve caps, they are usually green. Barrett

Only recently has my Caddy dealer put the 'green' valve caps on my tires when they filled them up with nitrogen. They never did it before so it must be something new or they never cared before or they just didn't have any of those pretty green caps.

They look stupid and I'm going to swap them for the original caps this week as I'm taking the "V" to a shows Saturday and I don't want the green caps on it then.

[Vettehead Mikey]

They look stupid and I'm going to swap them for the original caps this week as I'm taking the "V" to a shows Saturday and I don't want the green caps on it then.

Don't blame you. Sort of like having an 'L' tattooed on your forehead.

[NORTY]

N atoms and O atoms are the same size. N atoms are inert. O atoms can cause oxidation (duh!)
The only benefit to using N is the reduction of oxidation on the wheel surfaces and the TPMS unit.

A tire's pressure with N vs. ambient air will rise and fall at the SAME rate with the corresponding temperature change.

[BLACK MOON]

This another angle of the scam/myth. If the nitrogen molecules were larger and therefore didn't escape, a tire filled with 'regular air' would eventually become filled with pure nitrogen all on it's own. The tire walls would act like a filter and let only oxygen molecules through.

Funny how the scam artists don't have answers for this and the other points above.

I think seperating molecules is a little harder than filtering them.

[NavVette]

Ok...Here's for all you backyard chemists!!
Nitrogen, found on the periodic table of the elements is number 7, Oxygen is number 8. (Nitrogen weighs less!!) The Nitrogen atom is 155 picometers (pm) in diameter, the Oxygen atom is 152 pm in diameter. Nitrogen is a larger atom by 3 picometers or 0.000000000003 meters. To have nitrogen gas, the molecule is made up of two nitrogen atoms (N2). Oxygen is similar (O2). All this means that yes, if we are discussing absolutes and picometers...N2 is a larger molecule (by 6 pm). A similar nearly identical relationship exists for specific heat capacity and density therefore, the N2 response to temperature changes in the tire will be very, very close to that of O2. At least so close that you will not be able to tell the difference with even a digital tire gauge!!
Another interesting fact is that, the air all around us (normally compressed into an air tank for tires!!) is composed of 78.08% real, honest to goodness, Nitrogen (N2). Interestingly, 20.9% of the all natural (depending upon where you live!!) air around us is oxygen (O2). The remaining 1.02% is made up of others like argon, carbon dioxide (we breath out and plants breath in!!) Typically, the average 1% moisture content in air won't do much toward accelerating oxidation since most wheels these days are no longer made of iron. Aluminum, Magnesium, Stainless Steel and Chrome don't really oxidize like good 'ole iron!!
Final technical judgment: Use the air at any convenience store (since their aren't many "Full Service" stations any more). Save the $40 you'd spend on nitrogen. Air won't leak out any faster or slower than nitrogen! Most of the air is already nitrogen so, if it seems to expand and contract a lot between hot tire on the road and cool tire sitting in the garage, 78% of that difference is due to nitrogen. Lastly, unless you plan to keep your wheels on that single set of tires forever, oxidation is not going to be an issue for either the wheel or the TPS!! Oh yeah...the green caps on the tire stems is just so the dealer can more clearly see another "sucker" coming!!