Saw a Nitrogen sticker on a car. . .

[Texas42]

I was walking through my parking lot at the Hospital and saw a sticker stating that the tires were filled with Nitrogen.

I have no idea why. I think N2 might have a different density that could make the car drive better, but I have no idea.

Any clue?

 

[baboon]

Supposed to give better mileage.

 

[Exile Machine]

If I recall my high school chemistry, Air is 78% Nitrogen by volume. Nitrogen is not inert. It reacts with other elements to make things like fertilizer and ammonia, and DNA.

I believe the whole "Fill your tires with Nitrogen" thing is a Scam. I use a specially formulated 78% mix of nitrogen, oxygen and trace noble gases. I get it for 50cents at the gas station from the AIR hose.

 

[kingofwylietx]

You can pay extra to get Nitrogen in your tires. The only advantage is that it won't expand or contract as much as plain air. This is what they base the 'better fuel mileage' on, that they like to tout. However, your tires are designed to operate just fine on standard air when inflated to the proper pressure. It's a waste of money.......IMHO.

 

[Texas42]

nitrogen is inert, and doesnt fluctuate as much as air does.

contraction and expansion are better controlled, less prone to overheat blowouts...

All right, back to chemistry. PV = nRT

I don't see how nitrogen would fluctuate any more or less than normal, mixed air, oxygen gas, or CO2. I don't believe the pressure is too high/ or the size in the molecules to be that different that you have to use the more comlicated formula (that I don't remember off the top of my head. I know it has a nother couple variables a and b that acount for the mass and volume of the molecules)

ps- N2 is essentially inert. It requires special enzymes/catalysts to convert it to anything else at a reasonable rate. And only a few kinds of living things possess them. Legumes (sp?) and some bacteria.

 

[dee]

Pure nitrogen has no moisture either like compressed air which is better on your steel wheels. Also the expanding contracting has alot to do with it all tires will bleed off some preasure with time through the rubber and metal compounds. I have tried it and it works very well there is also a reason almost all your high end racers and race teams use it in their tires.

 

[navyguy]

I'd never pay for it, but when we bought Paula's Camery, it came with N2 in the tires, and the dealer said they would refill them at no cost for as long as we owned the car. (probably salesman speak) We had to have a tire replaced, and I have never been back to the dealer to have them put N2 in.

 

[Texas1911]

I have tried it and it works very well there is also a reason almost all your high end racers and race teams use it in their tires.

The tires on a race car reach 250 - 300 degrees on the surface on a hot track being pushed hard. Your car's tires on a 100 degree day are maybe half that at most.

The reason race teams do it is to eliminate moisture from the system, and work with just gas. Nitrogen is a cheap gas, it works, isn't explosively flammable like hydrogen and oxygen, and the race engineers are happy.

The nitrogen filled tires thing is a bit of a gimmick. The ideology is the N2 (two triple-bonded Nitrogen atoms) is less likely to diffuse through the tire carcass. There would need to be a HUGE disparity in porosity between the two gasses to really show a difference in a car tire.

 

[Texas1911]

Pure nitrogen has no moisture either like compressed air which is better on your steel wheels.

There is no method to avoid moisture. When the tire is mounted it is already containing 1 ATM of standard atmospheric gas.

 

[dee]

There is no method to avoid moisture. When the tire is mounted it is already containing 1 ATM of standard atmospheric gas.

Thats why the nitrogen machine pulls all the air out then puts nitrogen in then does it again.

 

[dee]

And for what its worth the wife has nitrogen in her short bus she drives around in and tire preasure has stayed at 38psi for the last 2.5 years I know this becouse I check them weekly and it has a tire preasure monitering system. I can't say the same about my junky ass dodge have to add air about every month or two.

 

[M. Sage]

There is no method to avoid moisture. When the tire is mounted it is already containing 1 ATM of standard atmospheric gas.

You can purge 'em. I know I've seen some high-end high performance wheels that have two valve stem locations on them at 180 degree intervals for purging.

You'd be surprised just how much porosity tires and wheels often have. Eliminating the oxygen also should help the tire carcass age less.

 

[Exile Machine]

Let the car talk guys weigh in on it:
Car Talk

 

[dee]

O yes car talk about as believable as box-o-truth in my opinion.

 

[M. Sage]

O yes car talk about as believable as box-o-truth in my opinion.

I've listened many times and rarely disagree with what they say on matters of auto repair.

 

[Exile Machine]

You don't have to take the car guys' word for it but their analysis does make sense.

 

[Texas42]

I still think the "expanding and contract less" is BS, but N2 is less reactive than oxygen. . . . though I think you need to replace your tire faster than the inside of your tire oxydizes.

 

[M. Sage]

No, N2 is definitely more pressure stable across a range of temperatures. Gases like water vapor and CO2 that are components of atmospheric air will have great amounts of variation due to temperature.

 

[JKTex]

nitrogen is inert, and doesnt fluctuate as much as air does.

contraction and expansion are better controlled, less prone to overheat blowouts...

That's it exactly. Airplane tires run it fr obvious reasons (extreme pressure and temp changes) but on the street, most auto's really won't see much benefit unless the tires see some kind of extreme condition. I doubt a good tire will feel or handle much different just because the temp and pressure is more consistent, but I've never done it so I can't say.

Trailer tires on the other hand, would be worth it in many cases. In most cases, trailer tires will be inflated to the max (or beyond depending on speed and weight but that's a whole other story) and would greatly benefit from a consistent temp for consistent pressure. Especially since a lot of trailer tires aren't protected from the elements and sit for long periods of time which kills them much faster than tires ran more often.

Several shops like Kwik Kar are starting to offer it. I'm sure at the local corner shop level, for the most part, it's just another way to separate people and their money if they can convince people it's better some how. I think most/many RV, trailer places and some Truck stops have it also. Places where it's use is truly a benefit.

 

[Texas1911]

Trailer tires on the other hand, would be worth it in many cases. In most cases, trailer tires will be inflated to the max (or beyond depending on speed and weight but that's a whole other story) and would greatly benefit from a consistent temp for consistent pressure. Especially since a lot of trailer tires aren't protected from the elements and sit for long periods of time which kills them much faster than tires ran more often.

On something like a big rig I'd probably run it as well.