Air vs. Nitrogen

[slug]

Recently I bought new tires for my truck at Costco. I found out that they're now filling all their tires with nitrogen. I read their little pamphlet at the desk and it said that nitrogen gives a better ride and they stay inflated longer because the molecules are larger and don't seep through the rubber as fast as plain air. Personally, I think it's another gimmick. Thoughts?

[pete roper]

ARRRRGH!!!!! What's f@cking air made out of mostly??????

 

Pete

[Guest Mattress]

Recently I bought new tires for my truck at Costco. I found out that they're now filling all their tires with nitrogen. I read their little pamphlet at the desk and it said that nitrogen gives a better ride and they stay inflated longer because the molecules are larger and don't seep through the rubber as fast as plain air. Personally, I think it's another gimmick. Thoughts?

 

Better ride? I think that is probably crap. How can you objectively quantify that anyway?

 

Bigger molecules, slower deflate..........I don't have my chemistry books anymore, but I think that is sus too.

 

However, N2 is an inert gas and I can see a benefit being less degradation of the hydrocarbon compounds of the tyres through oxidation.

 

Actually, you should demand helium. It has thermal conductivity almost as good as hydrogen, but less reactive, so should help your tyres cool themselves as well as saving you precious grams of unsprung weight. Not to mention all the funny voice jokes you can do at rallys after a case of beer.

[Alex-Corsa]

Recently I bought new tires for my truck at Costco. I found out that they're now filling all their tires with nitrogen. I read their little pamphlet at the desk and it said that nitrogen gives a better ride and they stay inflated longer because the molecules are larger and don't seep through the rubber as fast as plain air. Personally, I think it's another gimmick. Thoughts?

 

Yeah that's crap , perhaps to have some application in high speed hot weather, F1 class, as nitrogen can remain more volume-steady than air.But for the real world it's a bit of too much theory and no difference

[Cliff]

I don't buy it either.

 

Air is about 80% nitrogen and 20% oxygen. If it does leak badly you have a flat tyre of nitrogen and when you top it up with air you now have a mix of about 95% nitrogen. Next time it gets better still

[Tom M]

Somewhere on his website Jay Leno has (had?) a little video where he extolls the virtues of nitrogen as a tire inflator. IIRC in addition to nitrogen not degrading the tire, not leaking down like air, and not being as temperature sensitive as air, it also doesn't carry moisture like air so your rims won't corrode on the inside as quickly. Seems like a good idea to me if you have access to it.

 

Lots of cool cars and bikes here: Jay Leno's garage

 

I saw a segment of some car show on the tube about some of Jay's cars and bikes a while back and I noticed a V11 Lemans in his garage, so he may be somewhat of a Guzzi guy!

[Guest ratchethack]

Heh, heh. . . . . Winter's well on its way in the Northern Hemi, ain't it?

 

Here's a company's Web site that mfgr's and sells nitrogen generation equipment, one specifically for tires.

 

http://www.southteksystems.com/aboutus.asp

 

I'm sure it makes a difference -- to somebody.

 

Nitrous oxide, N2O, on the other hand, is a different bird altogether, a well-known inhalant, and well known to be relied upon -- and well trusted -- as the alternate "logic stimulant/propellant" of choice of some visitors to Earth from planets of alternate universes, where its evidently a primary component of the natural atmosphere.

 

Evidently, some find it useful for formulation of the basis of their world views and political positions.

 

What Does Nitrous Do?

 

Physiological effects last a minute or two for a lungful of nitrous and then mainly dissipate. Some residual effects may last up to several minutes later. Unlike other drugs, the effects of nitrous very rapidly recede, but under chronic exposure, toxic effects are observed. As noted in 1845, "Those who inhale the Gas once, are always anxious to inhale it the second time." When inhaled, nitrous produces a variety of physical effects including:

 

Disorientation (both spatial and time-based)

Fixated vision

Throbbing or pulsating auditory hallucinations

Similarly pulsating visual hallucinations

Increased pain threshold

Deeper mental connections

Lowered vocal pitch (opposite of helium)

 

What Are The Dangers?

 

The most common dangers from nitrous are due to its disorienting effects and the silliness that surrounds something called laughing gas. Tripping, falling or tipping over in a chair are very common. In one recorded case this caused death. The main cause of death from nitrous seems to be asphyxiation from a bag over the head. Frost bite from the very cold gas is also a concern, especially if dispensing when still disoriented.

 

Use common sense to avoid most problems. (Presumably, the "common sense" referred to here would be based on breathing Earth atmosphere for extended periods after ingestion of N20, so as not to taint common sense with "laughing gas sense". )

 

Because nitrous permeates the lipid (fatty) membranes of your body, it can outgas into your gut or middle ear causing an ache. Chronic heavy usage has very unpleasant effects that could be permanent. Read more detailed dangers of nitrous use.

 

What Does Nitrous Feel Like? (an anonymous personal account)

 

After several deep breaths of air, I inhale nearly a lungful of

nitrous and pull some air down on top and then hold my breath.

Within seconds, a light tingling can be felt which seems to

increase in frequency. The sensation is much as if waves were

traveling up your body or as if you were twisting or spinning.

Disorientation increases rapidly and the pulsing sounds/feelings

increase, wrapping over one another. It is now, with eyes shut,

that I enter a dreamlike state, where I am thinking out something

and the external world has essentially ceased to exist. The

urge to breathe takes over at some point and partial or whole

breaths taken. Open eyes reveal some sort of tunnel vision,

with regions of disorientation about the outside. Slowly the

throbbing subsides.

 

At other times I experience a sense of paranoia mixed with disorientation.

I have a deep conviction while under the influence that all things are

cycling together, that there is some deeper cyclical event occuring. It

is as an experience of deja vu continually occuring. The feeling is

profound and not altogether pleasant.

 

It is at this point that my world view becomes clear, and I'm ready to vote.

 

[felix42o]

FWIW, we use the nitrogen in aircraft tires 'cause it's more stable WRT temp changes and doesn't develop moisture like O2 that can cause corrosion. Also supposed to hold pressure longer. All this is, of course, on aircraft tires running 100-175 PSI, so don't know how or if those benefits transfer to a car tire running 35 PSI.

[Guest Nogbad]

Snake gas.

 

O2 does not react significantly with the rubber inside a tyre, old tyres crack on the outside, mostly due to sunlight. My understanding is that N2 is used in aircraft tyres to limit corrosion of the light alloy wheel and also to reduce the effect on a possible fire / tyre burst interaction.

 

Pointless on cars and bikes, but it makes money for someone. As they say, a fool and his money are soon parted.

[Guest Mattress]

Snake gas.

 

O2 does not react significantly with the rubber inside a tyre, old tyres crack on the outside, mostly due to sunlight. My understanding is that N2 is used in aircraft tyres to limit corrosion of the light alloy wheel and also to reduce the effect on a possible fire / tyre burst interaction.

 

Pointless on cars and bikes, but it makes money for someone. As they say, a fool and his money are soon parted.

 

Did the Concorde have N2 in the tyres, or was it hydrogen?

[Rusty Bucket]

I think Nog hit this one. The 'big' benefits of pure nitrogen may be in the superior compression equipment that YOU the consumer are paying for. Getting the moisture out of compressed air is a problem in high volumes, and that moisture is what is harmful to your rims. You can never get all the air out, or all the moisture, unless the tire was changed/beaded up in a sealed vacuum, but as far as moisture goes, some effort in keeping it to a minimum is well justified. I don't favour nitrogen over dry air, but compression equipment at a tire store is one of the big battles/expenses they fight. The nitrogen equipment has excellent drying capability, and tends to be new (for the time being) and in good repair, as the shop bills directly on the output. If you live in a humid environment, it might be worth it for you. If not, you can save some money.

[Dan M]

Recently I bought new tires for my truck at Costco. I found out that they're now filling all their tires with nitrogen. I read their little pamphlet at the desk and it said that nitrogen gives a better ride and they stay inflated longer because the molecules are larger and don't seep through the rubber as fast as plain air. Personally, I think it's another gimmick. Thoughts?

 

 

This has been getting some play in the aftermarket. Primarily by the equipment manufacturers trying to sell the product. It is catching on with the tire shops and with the quick oil change places as a profit center that requires no technical knowledge. This is a good thing because they generally don't have any anyway. In northern climes where there are big temperature swings your pressures will not vary as much. Also with alloy wheels which tend to corrode at the bead seal and develop slow leaks, they theoretically will leak less due to the larger molecules. That said, I see it as a problem that didn't need fixing. If you service your car regularly and get the tires checked at the same time there is really no need for anything but air in there. If you do develop a rim leak it will likely worsen over time and the precious nitrogen will escape anyway.

[Ryland3210]

I have heard before that nitrogen leaks less than oxygen because it has bigger molecules. Nitrogen has an atomic number of 14 versus oxygen's 16. In air, both are diatomic, so it seems to me that belief is illogical.

 

Helium, an inert gas, has a much lower atomic number (I think it is 4), and is monatomic. It is used for leak testing because leaks are then so much easier to detect, for example on air conditioning compressors. Its atoms are much smaller than either N2 or O2.

 

Butyl rubber is used to line tires because it is less permeable than the casing rubber, but more expensive. So the leakage rate depends on how much the manufacturer wants to spend, or how light a high performance tire needs to be.

 

As far as thermal stability is concerned, both nitrogen and oxygen obey the same relationships between volume, pressure and temperature under steady state (PV=nRT). However, for short term rapid changes in volume, as you might have hitting bumps or landing an aircraft, I recall the adiabatic (that is, without heat transfer) relationships are different. All this is standard freshman year college chemisty for those interested.

 

I think the best reason for using nitrogen is corrosion inhibition simply because is likely comes from a dryer source than the typical air compressor, and doesn't "oxidize" rims. I wonder if the oxygen in air in some way combines with the hydrogen in the rubber compounds to form water?

[jrt]

Um..cough....bullshit....cough. You can trust me in this if nothing else- I do have a PhD in chemistry.

Air is 78% nitrogen, the rest is mostly oxygen. There's a smattering of other gasses and water. The difference in behavior between the two gasses, O2 and N2, is nothing we will ever experience unless we drive our Guzzi's on Saturn. From a tire's perspective, those gasses are identical. Yes, O2 is more reactive, but it doesn't react with rubber fast enough to make any difference.

One advantage of "nitrogen" over "air" is that it has less moisture in it (if it actually is purified nitrogen). As the tire heats and cools, less water will condense inside the tire- therefore less corrosion of the rim. I think this is about it.

Dinitrogen is the same size as dioxygen. Dinitrogen has the same compression characteristics as dioxygen anywhere near "normal earth" conditions.

[Orson]

I've often wondered if helium would reduce my unsprung weight.