So i roll up to costco, and i see a sign that says...

NITROGEN FILLED TIRES....BETTER HANDLING...BETTER GAS MILEAGE...ETC

now how can you even justify paying 40 to get your tires filled up with nitrogen? How are people on this earth sooooo stupid that they actually believe something of this nature will actually do something worthwhile. Is there any sort of proof/evidence that might suggest it is better than air? Please enlighten me.

John

thats what I heard. I can get all four done for 10 bucks here.

its a new fangled thing. but what happens if your tire is low on psi, how are u gonna fill it up? theres no gas stations that offer nitrogen fillups

I heard that the N2 will actually eat your tires up.....but then again thats just a rumor.

but how is nitrogen suppost to be beneficial? All it is, is a gas like air that keeps aour tires inflated. Why is one type of gas better than the other?

John

I heard about this on motorweek on the speed channel and they said it really does work. "When you put nitrogen in your tires then your tire pressure remains constant."

Heres an article about it: http://www.waff.com/Global/story.asp?S=2399797&nav=17jVRjuL

There are nitrogen around us in air, and outside of the tire. So N2 will not eat up tire. The only benefic i heard is they don't change pressure that much when the tempture change.

Ok the real benefit from using the nitrogen is that the molecules are quite a bit bigger than regular oxygen molecules and in turn will not seep out of your tires over time. Where the oxygen molecules will seep out. Also the nitrogen will not expand or contract while being hot or cold, so your tire pressures remain the same all the time. I have had nitrogen in my car for almost a year now and have not dropped in pressure at all. It is definitely worth the 40 dollars to get them filled. The only way that you will need a refill is if your tire would get punctured from a nail or something.

Hope this helps

yes. . . the air that we breathe is mostly composed of nitrogen. . . pure nitrogen would be less sensitive to changes in temperature than the the oxgen, nitrogen, and other crappy gas mix that exists in our air. . . but is it worth $40. . . dunno bout that.

dude, im just going to fill them rubbers up with helium, cause my tC is straight up flying

:doh:

I asked my father-n-law about this. He has been a mechanic for over 30 years. He also works on Military jets now. anyway, check out this article on Nitrogen for jet plane tires.

http://www.physlink.com/Education/AskExperts/ae192.cfm

Dont remember where I found this! But, I put it in quotes.
[i]Nitrogen filling stations at tire dealers are becoming more common. This is a fairly big deal for the consumer. One of the biggest reasons for premature tire wear is improper inflation pressure. Assuming that a tire was inflated to the recommended pressure at the time of installation, it will overinflate from normal road friction as it becomes heated, or heated from a hot sun on the black sidewalls. When the temperature drops as it often does in the Northern latitudes, the tires will become under-inflated and start scrubbing. In the Fall, when you typically see wide temperature variations, keeping your tires inflated to the proper pressure is a time-consuming and difficult chore, and that's why most people don't even bother, especially on big rigs. With Nitrogen-filled tires, this problem is solved. Nitrogen is a totally inert gas and does not expand or contract with temperature. So if your tires were inflated to their proper inflation at installation, say 100 psi, then they will be 100 psi at 30 degrees and 100 psi at 115 degrees.

The added bonus with Nitrogen is there is no moisture
in your tires."

Look for a nitrogen filling station in your area. Nitrogen can extend tire life by 25 percent, improve fuel economy, eliminate rim corrosion, and tires will run cooler.

Sounds good to me... But I'll wait until I see it for $10 instead of $40!

Just remember... Don't put liquid nitrogen in your tires...

Interesting!

I can't remember the number, but our air is overwhelmingly mostly nitrogen (80% maybe?). so, if the smaller crap leaks out, then over time refilling your tires as they drop in pressure will eventually leave your tires with all nitrogen (as the limit of fill ups reaches infinity the presence of smaller molecules like oxygen goes to 0, simple calculus.).

X + (100-X)*80% = X where X starts at 80. So after one refill, you’re at 96% N2, After a second you’re already at 99.2% N2. So, I’d say $10 or $40 for a fill up of N2 is a waste.

Nitrogen N2 78.084%
Oxygen O2 20.947%
total 99.998%

George will chime in with the real formula shortly, since I can't remember math notation anymore.

(pseudo code below)

double ntwo, n = .78084;
double target = .999;
int count = 0;
while(n<target) {
n=n+((100.0-n)*ntwo);
count++;
}
out.println(Integer(count).toString());

I agree that using nitrogen keeps the tires free from moisture.

The inmediate benefit is that with the moisture out , there is less mass of gases in the tire (N2 mass + H2O mass) therefore reducing heat build up.

This means that a tire filled with regular air is more likely to overheat due to temperature and friction than one filled just with nitrogen that, by the way, will come dry off of the bottle due to the particularities of the bottling process (cryogenic process).

Regular air for tires is obtained from air compressors. Is a fact that the air we breathe contains moisture, or water, that if is not removed will make its way up to the tires. Also air compressors work with oil, so if no actions are taken oil will also make its way to the tire. Nobody knows the operation conditions of air compressors at gas stations or how are they maintained. To find good quality air is a lottery unless we know facts about a particular gas station compressor.

In a manufacturing environment, every time I install a piece of machinery that needs dry and clean air, I make myself sure to install an oil remover (coalescent filter) and an air dryer before the comsuption point.

Now, I have to clarify from an engineering standpoint that IS NOT TRUE that nitrogen will not change its volume with the temperature.

Nitrogen, as any other gas, behaves according the IDEAL GAS LAW, and IT DOES CHANGE its PRESSURE according to the TEMPERATURE and MASS existing in the container (tire). The equation that governs the pressure/volume/temperature changes is PV=nRT. It can be found in any thermodynamics book.

Probably what the people may perceive as no pressure change is that proportionally, for the same temperature differential, the pressure change for the air is greater than for nitrogen.

Just my 2 cents :idea:

QUESTION: I would like to know if there are any other Mechanical Engineers at ScionLife or this forum - thanks

i work at costco in my area. i do not work in the tire center but i do about what goes on and what we offer out there. when my tC comes in i will be putting nitrogen in my tires from what i have heard from the manager out there. nothing but good things. yes it might be $40, but if u can get it from costco its about $10 cheaper than anywhere else. ill ask at work and see what i can find out

Also, the molecular size does not play any rol in how fast a tire losses air. It is a sealability issue. The tire mounter must be sure to apply sealing compound to the lip of the tire before it is inflated to prevent leaks.

Is pretty difficult to separate air components at ambient temparatures. There is no such a thing like that oxigen will escape before the nitrogen if there is a leak. It takes about -300˚F / -185˚C to separate the air components trough a cryogenic process. There are also non-cryogenics processes that require special materials to reach the same goal. For more information check the link.

http://www.uigi.com/compair.html

:idea:

Awesome info in this thread!

But niguels pretty much shot down all the advantage points
I've read about.

Would you use nitrogen niguels?

yea we use nitrogen in the tires of our jets..lol hmmm i wonder if i can get one of those guys to hook me up :)

Still, paying $40 to up the nitrogen content in your tires from 82% (regular air) to 95% (they don't use pure N2 - too expensive to make) or so - not very smart.

one of the tire dealers here in cincy actually uses N2 inflation as a selling point. If you buy tires from them you get N2 inflation for the life of the tires. I'm pretty sure the military and the police use it, and maybe even the fire department and ambulance, so there must be some good to it.

I would get it if were cheap, but not spending 40$

If I can find inexpensive nitrogen I would use it. It comes pure and dry right off the bottle. When I say dry is "Free of Water". That is good for the tires.

I think is a personal decision because of the cost, but nitrogen is definitively better that plain air.

is it better than plain dry air though? Maybe O2 and N2 don't get along well and ____ eachother off, raising the temp levels in the tire?

I thought the O2 leaking thing sounded goofy, when you're talking about a single molecule then I doubt a leak is small enough for one to stay in and another to get out as a rule.

Hey, and O comes after N on the chart.. does that mean it's bigger? (I know it's heavier.. but does that correspond to volume?)

The problem with the air is not the air itself, it does not have anything to do with the components N2 or O2.

THE PROBLEM is the water that comes from the air compression process, water that is in the air as moisture, water that will increase the mass of gases inside the tire and then... the more mass of gases, the more dificult for the tire to dissipate built up heat.

Now, if you can find an air compressor properly set-up with an air dryer and oil remover, that is capable of providing clean and dry air... THEN USE AIR.

But, since is more likely that you are going to find bottled nitrogen than a nicely set-up compressor at a tire shop, then I think Nitrogen is better than Plain Air.

My thoughs are based on what you can realistically obtain from the market.

That''s interesting I would've never thought abt putting N2 in my tires. Where can you even get that done in SoCal?? :eyebrow:

I've got a propain tank out back. That should do the same thing, I figure.

Propane is FLAMABLE, Nitrogen is not.

Well, if you fill yours with propane you may give a blown tire a whole new meaning.

:rofl:

Propane is FLAMABLE, Nitrogen is not.

Good thing too. Think of the mess to clean up the day man made fire.

QUESTION: I would like to know if there are any other Mechanical Engineers at ScionLife or this forum - thanks

Yeah, Im a degreed engineer and I'll sort of agree with you. Pure nitrogen is indeed "dry" or it wouldnt be pure nitrogen gas. Thats the primary advantage of having it in your tires. The problem with water in your tires doesnt have to with the waters mass but how that water vapor expands as its heated by the rolling resistance of the tire. Think steam engine. This continually varies the temp of the tire as well as the pressure so its impossbile to be consistent.

Nitrogen diffuses about 3 times more slowly through typical tire compounds than air, so it stays inflated longer.

You can mix air with nitrogen if you need to, it wont hurt anything but it removes the benefits of pure nitrogen.

It helps to have dual valve stems so you can completely purge the air from the tire as well. Most racing wheels have these.

http://www.tirerack.com/images/wheels/kosei/swap/kosei_k1_ts_ci3_l.jpg

The tirerack guys can probably elaborate more on this.

--
Cheese

Yeah, when I said water I really meant vapor. You are right.

Good post "macncheese". It really helps to bring some light to the air-vs-N2 conversation.

Thanks

I just know someone's going to misread this thread and put Nitrous in their tires... or maybe nitro... hehehe

Seriosly, tho, thanks for cutting thru the hype...

Propane is FLAMABLE, Nitrogen is not.

Well, if you fill yours with propane you may give a blown tire a whole new meaning.

:rofl:

Hahaha...no kiddin'

"Earth’s atmosphere is 78 percent nitrogen, 21 percent oxygen, and 1 percent other gases."

There is a 22 percent difference in nitrogen content if one fills their tires with pure, dry, nitrogen.

I suspect that the lack of oxygen might lengthen the life of the tire's interior, but I don't really know of ANYONE who has worn their tires out from the inside... :lalala:

Lack of water vapor will make the pressures more stable, but I suspect that could be seen with any anhydrous mix, including plain old dehydrated, filtered air.

In my real-world use of tires on the street will there actually be an appreciable difference? I doubt it.

(I also wonder about the outgassing of the new tire compounds, and how quickly that outgassing will totally muck up the 'pure' nitrogen mix, anyway.

Bottom line: Yes, pure nitrogen in the tires probably presents advantages in specific uses - and yes, when I used to work on B52's, we had nitrogen in their tires - of course we also had antifreeze in their fuel, and started them with an explosive charge... different environments, different requirements.

$40 for a tire fill?

Thanks, I'll pass... :yawn:

Tires that didn't change pressure with temperature would be wonderful, but the simple fact is that filling them with nitrogen isn't really going to affect that. Just look at the ideal gas law:

pV=nRT

where p is pressure, V is volume, n is the number of molecules of gas, R is a constant and T is temperature. notice that it doesnt specify which gas it's talking about, because it doesnt matter.

When temperature (t) goes up, pressure and volume must go up too to keep the equation balanced.

The less moisture thing is probably true, im not really sure why having moisture in ur tires would be a bad thing though.

dude, im just going to fill them rubbers up with helium, cause my tC is straight up flying

___.

Propane is FLAMABLE, Nitrogen is not.

Well, if you fill yours with propane you may give a blown tire a whole new meaning.

:rofl:

You shold read the label on a can of "fix-a-flat" sometime! :)

There's a lot of retoric about how dry nitrogen is better than air, but the real reason that racers use nitrogen is that it is the cheapest inert gas that comes in high-pressure bottles. A nitrogen bottle is a lot more portable in the pits than a compressor!

Why do military jets run nitrogen? They run pressures in the hundreds of PSI, so ordinary compressors won't fill 'em. Nitrogen was already available for filling oleo struts (where you also need very high pressures) so why not use the same bottles for filling the tires?

For those that are put off by the $40 cost of a nitrogen fill, I'll be happy to fill your tires with 80% nitrogen for only $32! :)

George

:rofl: seriously, i was thinking about how long it takes for my tire pressure go down, and id rather check my tire pressure once every one or two weeks and fill them up for free rather than pay $40 for 20% more nitrogen than im getting.

John

Propane is FLAMABLE, Nitrogen is not.

Well, if you fill yours with propane you may give a blown tire a whole new meaning.

:rofl:

You shold read the label on a can of "fix-a-flat" sometime! :)

There's a lot of retoric about how dry nitrogen is better than air, but the real reason that racers use nitrogen is that it is the cheapest inert gas that comes in high-pressure bottles. A nitrogen bottle is a lot more portable in the pits than a compressor!

Why do military jets run nitrogen? They run pressures in the hundreds of PSI, so ordinary compressors won't fill 'em. Nitrogen was already available for filling oleo struts (where you also need very high pressures) so why not use the same bottles for filling the tires?

For those that are put off by the $40 cost of a nitrogen fill, I'll be happy to fill your tires with 80% nitrogen for only $32! :)

George

George: I was just referencing the joke that superjeer made about filling up the tires with propane. We were joking about the propane thing :wink:

Also, I already read the label of fix-a-flat, but I still don't know what was your point. Could you please clarify it.

By the way, if you want to read something way better than just the label of Fix-A-Flat follow the link to the database of household products.

http://householdproducts.nlm.nih.gov/cgi-bin/household/brands?tbl=brands&id=16004032[/u]

I think is a personal decision because of the cost, but nitrogen is definitively better that plain air.

I have to quote myself before people starts flaming.


:flame:

Tires that didn't change pressure with temperature would be wonderful, but the simple fact is that filling them with nitrogen isn't really going to affect that. Just look at the ideal gas law:

pV=nRT

where p is pressure, V is volume, n is the number of molecules of gas, R is a constant and T is temperature. notice that it doesnt specify which gas it's talking about, because it doesnt matter.

When temperature (t) goes up, pressure and volume must go up too to keep the equation balanced.

The less moisture thing is probably true, im not really sure why having moisture in ur tires would be a bad thing though.

You answered your own question. .. because moisture becomes vapor and then we've got more V for our PVnRT. Nitrogen is a bigger molecule so there are less of them (n) so T doesnt vary as much (therefor P and V dont vary as much).

don't know why this has not been done sooner....lol

Moved to tread and butter....

George: I was just referencing the joke that superjeer made about filling up the tires with propane. We were joking about the propane thing :wink:

Also, I already read the label of fix-a-flat, but I still don't know what was your point. Could you please clarify it.

By the way, if you want to read something way better than just the label of Fix-A-Flat follow the link to the database of household products.

http://householdproducts.nlm.nih.gov/cgi-bin/household/brands?tbl=brands&id=16004032[/u]

Read this label and you'll see what I was getting at:

http://householdproducts.nlm.nih.gov/cgi-bin/household/brands?tbl=brands&id=7006002

Fix a flat used to be mostly propane, but I apparantly they have changed their formula to something a bit less dangerous.

George

blastedat9:

Get 2 pieces of any material and make Object A to have 100 times the mass of Object B.

Heat them up until reaching, lets say 300 F, and then remove the heat source so both objects, A and B, starts cooling down. The ambient temperature is 70 F.

Question: which one of the objects will reach 70 F first.

Answer: The one with the least mass.

What do this means: a tire with a mixture of water vapor and air inside will retain more heat than a tire filled with dry air or nitrogen. Heat build up is not god for tires, right?

Now, probably this conversation is losing real meaning because is getting to the point that no tire inflated with air is good. No, that is not what I wanted to say.

A tire failure due to a high content of moisture is an extreme case, but not an unlikely scenario.

I just tried to point out why nitrogen could be superior to plain air, but probably real world advantages cost/performance wise are hard to notice.

Regular air is fine for most applications and the use of nitrogen is a personal decision.

peace to everybody :wink:

George: I was just referencing the joke that superjeer made about filling up the tires with propane. We were joking about the propane thing :wink:

Also, I already read the label of fix-a-flat, but I still don't know what was your point. Could you please clarify it.

By the way, if you want to read something way better than just the label of Fix-A-Flat follow the link to the database of household products.

http://householdproducts.nlm.nih.gov/cgi-bin/household/brands?tbl=brands&id=16004032[/u]

Read this label and you'll see what I was getting at:

http://householdproducts.nlm.nih.gov/cgi-bin/household/brands?tbl=brands&id=7006002

Fix a flat used to be mostly propane, but I apparantly they have changed their formula to something a bit less dangerous.

George

Ok, I got the point. Probably they got sued because somebody got harmed and were forced to improve the formula.

Good to know about the propane content. Thank you

:wink:

Tire shops hate working on tires that have this sort of stuff in them. Dangerous, flammable, and explosive!

George

I remember (many moons ago) when I managed a mountain
biking team...one of the guys was always late to races and
training and whatever, and the first thing he'd do is go to
the bathroom (after showing up late).

One day we emptied out the air in his bike tires, and used
a hand pump to fill the wheels up with water.

Funniest thing you've ever seen...you have no idea how
difficult it is to steer a bike when the wheels weight more
(each) then the whole damn bike! LOL

Back on subject though…if you guys know anyone that
Paintballs, they use nitrogen as standard now. So if you
know someone that runs a field or has their own home
fill setup, maybe they can hook you up? It’s been years
since I’ve done any paintballing, I don’t know anyone
with the gear anymore…

Ok the real benefit from using the nitrogen is that the molecules are quite a bit bigger than regular oxygen molecules and in turn will not seep out of your tires over time. Where the oxygen molecules will seep out. Also the nitrogen will not expand or contract while being hot or cold, so your tire pressures remain the same all the time. I have had nitrogen in my car for almost a year now and have not dropped in pressure at all. It is definitely worth the 40 dollars to get them filled. The only way that you will need a refill is if your tire would get punctured from a nail or something.

Hope this helps

$40 is worth not having to maybe pay 25 cents once or twice a year to adjust tire pressure? Come on now. Lets see, if your tires last 2 years (and many dont) that $40 will save you about 20 minutes of time and about $1 if you have to pay for air to refill them twice a year. I have never had to add air more than twice per year unless i had a bad valve stem or a hole in the tire. Sounds like someone is making a killing off of people paying for this kind of thing. And as was stated in one of the other posts, what happens when they do leak? You going to drive around with low tires untill you find a nitrogen fillup?

Ok, here's my question:

Can someone explain the process of replacing a tire's internal gas from plain air to nitrogen?

Is the plain air just released from the valve stem, and then once the pressure is low enough that no more comes out, it's refilled with nitrogen? If so, wouldn't that mean that a lot of plain air/moisture remains in the tire (albeit less than previously)?

:question:

http://www.tirerack.com/tires/tiretech/general/pressure.jsp
http://www.tirerack.com/tires/tiretech/general/airpress_vs_dryperf.jsp
http://www.tirerack.com/tires/tiretech/general/airpress_vs_wetperf.jsp

Again, tirerack.com rocks. Give them your business.

--
Cheese

Yep the tire will still have air in it even if its completely flat. You would have to use a modified refrigeration manifold with a vacuum pump to pull all the air out in tire and then gas it up with what ever you like. Argon, Xenon, helium, phosgene who cares lol. And yes, as u pull a vacuum on the tire you will be pulling moisture out and have a truely dry tire.

I once saw a tire filled with R-22...thats a hydrogen, florine, chrine, and carbon gas mix..........Try that on for size!

It filled up the tire in about 3.2 seconds and created a really nice whitewall frosting on it too lol. :rofl: :lalala:

Ok the real benefit from using the nitrogen is that the molecules are quite a bit bigger than regular oxygen molecules and in turn will not seep out of your tires over time. Where the oxygen molecules will seep out. Also the nitrogen will not expand or contract while being hot or cold, so your tire pressures remain the same all the time. I have had nitrogen in my car for almost a year now and have not dropped in pressure at all. It is definitely worth the 40 dollars to get them filled. The only way that you will need a refill is if your tire would get punctured from a nail or something.

Hope this helps

$40 is worth not having to maybe pay 25 cents once or twice a year to adjust tire pressure? Come on now. Lets see, if your tires last 2 years (and many dont) that $40 will save you about 20 minutes of time and about $1 if you have to pay for air to refill them twice a year. I have never had to add air more than twice per year unless i had a bad valve stem or a hole in the tire. Sounds like someone is making a killing off of people paying for this kind of thing. And as was stated in one of the other posts, what happens when they do leak? You going to drive around with low tires untill you find a nitrogen fillup?

It makes no sense to use nitrogen if you're just putting around. This isn't the sort of trouble that you go through to put in your Toyota Prius so you can have peace of mind while you drive to work.

Heat and tire pressure changes are much more noticeable at the track and that's why the kind of people that would use nitrogen are people who are using R compound tires on Kosei K1 TSes and purging all of the air out of their tires. Maintaining proper tire pressure throughout each lap is important to shaving off every millisecond, but you're not going to see a $40 benefit on your morning commute.

Good point uncompiled
:clap:

It makes no sense to use nitrogen if you're just putting around. This isn't the sort of trouble that you go through to put in your Toyota Prius so you can have peace of mind while you drive to work.


Tire pressure is extremely important to fuel economy so thats a pretty poor example. Serious MPGers run tire pressures in the mid 40s.

It makes no sense to use nitrogen if you're just putting around. This isn't the sort of trouble that you go through to put in your Toyota Prius so you can have peace of mind while you drive to work.


Tire pressure is extremely important to fuel economy so thats a pretty poor example. Serious MPGers run tire pressures in the mid 40s.

.... and notice very very small percentages of MPG increases

It makes no sense to use nitrogen if you're just putting around. This isn't the sort of trouble that you go through to put in your Toyota Prius so you can have peace of mind while you drive to work.


Tire pressure is extremely important to fuel economy so thats a pretty poor example. Serious MPGers run tire pressures in the mid 40s.

.... and notice very very small percentages of MPG increases

Are you kidding? More like 10-15%

Nothing new. Racers used nitrogen in tires back in the 60's. Nitrogen is a 'noble' gas, less variation in volume due to temperature, so tires were less sensitive to abuses of racing.

Better idea: Carry a pressure gauge and learn to use it... cost you less money, too1

Wow, you people actually believe this :rofl: ?

This is an old scam and is a total waste of money. Here's proof:

PV=NRT Pressure*Volume=N(no. of molecules)*R(constant)*Temperature

This is an old chemical law and cannot be disputed. The only way to change the tire pressure is to either remove or add gas, or change temperature. IT DOES NOT MATTER what gas is in the tires. Xenon, neon, oxygen, hydrogen, nitrogen, it all reacts the same to temperature changes.

I'm a chemistry major and this is a laughable attempt to steal your money. Just warning you.

http://www.cartalk.com/content/columns/Archive/1997/September/05.html

Here's a quick resource, but trust me, this is a very very old scam.

Wow, you people actually believe this :rofl: ?

This is an old scam and is a total waste of money. Here's proof:

PV=NRT Pressure*Volume=N(no. of molecules)*R(constant)*Temperature

This is an old chemical law and cannot be disputed. The only way to change the tire pressure is to either remove or add gas, or change temperature. IT DOES NOT MATTER what gas is in the tires. Xenon, neon, oxygen, hydrogen, nitrogen, it all reacts the same to temperature changes.

I'm a chemistry major and this is a laughable attempt to steal your money. Just warning you.

Sickboy

You are missing something important in your comments about this thread.

The point is not only wether pure nitrogen is better than pure air. They both are gases and their behavior can be approximated using the "Ideal Gas Law".

An important comparisson done in this thread is between the nitrogen that comes in pure state in bottles vs. the compressed air you put in you tires at any gas station. That air may contain moisture (or water) from the compressing process that, with heat, turns into vapor and in EXTREME CASES could lead to tire overheating and failure.

Also, for your information, all the gases do behave different. The use of the IDEAL GAS EQUATION (PV=nRT) is just an APPROXIMATION that assumes that all gases behave the same in order to simplify calculations.

You can still calculate particular properties of individual gases (to demostrate that they do behave different) by using more specific equations like the "Van der Waal's Gas Law", in which you have to feed gas-dependent values in order to determine either pressure, volume or temperature. And in case you have a mixture of gases (like the air), you have to calculate an specific constant based on the proportion of each component in the mixture.

Check it out in Internet and find it out for yourself.
:wink:

Link to the Van der Waal's Gas Law
http://www.hull.ac.uk/php/chsajb/general/vanderwaals.html

No, you're correct about the moisture but that's not going to effect anything as far as normal driving goes. I would be shocked if it could muster a .5 psi change.

I'm just saying this is a waste of money. Dealerships are thinking about it like this:

Hmmmm, what's another way to take money from people for doing next to nothing? I know, let's fill their tires with Nitrogen. See, it sounds like nitrous so some people might associate it with going faster. Next we'll have to take a small fact and blow it way out of proportion and we'll be ready to market this to the masses.

Sorry, if I sound like a jerk. I'm just trying to give people a head's up on this scam. Seriously this has surfaced and died several times before.

Besides, moisture expands when it cools. If anything the moisture actually fights the drop in PSI.

No, you're correct about the moisture but that's not going to effect anything as far as normal driving goes. I would be shocked if it could muster a .5 psi change.

I'm just saying this is a waste of money. Dealerships are thinking about it like this:

Hmmmm, what's another way to take money from people for doing next to nothing? I know, let's fill their tires with Nitrogen. See, it sounds like nitrous so some people might associate it with going faster. Next we'll have to take a small fact and blow it way out of proportion and we'll be ready to market this to the masses.

Sorry, if I sound like a jerk. I'm just trying to give people a head's up on this scam. Seriously this has surfaced and died several times before.

Besides, moisture expands when it cools. If anything the moisture actually fights the drop in PSI.

I agree with you, for everyday driving the difference may not be noticeable, needless to say not worth the money.

I am going to ask tomorrow at my job how much a nitrogen bottle costs in order to calculate how many fill-ups you can get from a bottle, but it seems to me that those guys that offer nitrogen at $40 the charge are trying to make a fortune out of people's lack of knowledge.

To everybody: always use common sense before making this kind of decision.

Chemistry major,
You're forgeting about phase change and the effect that it plays on density.

It makes no sense to use nitrogen if you're just putting around. This isn't the sort of trouble that you go through to put in your Toyota Prius so you can have peace of mind while you drive to work.


Tire pressure is extremely important to fuel economy so thats a pretty poor example. Serious MPGers run tire pressures in the mid 40s.

I concede. I wasn't trying to talk about people who are obsessed with every minute increase in fuel efficiency. I was just making an overgeneralization about people who drive mass-marketed econoboxes and only use their cars for driving to work -- you know, the kind of person who thinks of their car as an A-B mode of transportation, but doesn't even know what kind of car they own. I think this is a lot of money and trouble for what you get, but I won't say that the idea is a scam. The scam is charging people $40 to set their tire pressure.

It makes no sense to use nitrogen if you're just putting around. This isn't the sort of trouble that you go through to put in your Toyota Prius so you can have peace of mind while you drive to work.


Tire pressure is extremely important to fuel economy so thats a pretty poor example. Serious MPGers run tire pressures in the mid 40s.

.... and notice very very small percentages of MPG increases

Are you kidding? More like 10-15%

Yeah, sure. My friend told me the same thing about the "huge" differences he saw in MPG with tire pressure. After a lot useless work on his part of keeping close track of mileage, weather conditions, and tire pressure he was able to prove a whole .5 - 1% increase in mileage.. WOW. The changes in atmospheric conditions, and driving conditions also further complicate proving any of this and completely override the minute advantages you may or may not be getting. I check my pressure regularly, and see very small changes in the pressure over time (unless I actually have a leak). If you check it regularly and keep it within a few lbs of the spec, you will not see any significant changes in mpg. And as for running 5 - 10lbs over the spec.... that wears your tires out in an abnormal fashion (center wears faster), so the pennies you are saving in gas are wiped out by the loss in tire life. If you want to spend $40 to inflate your street tires with nitrogen, go ahead, its your money. But if you add it all up, you are losing in the long run. Now if you are running on a track, and pushing your tires to the limit, then all the little things make big differences..... not so on the street.

No, you're correct about the moisture but that's not going to effect anything as far as normal driving goes. I would be shocked if it could muster a .5 psi change.

I'm just saying this is a waste of money. Dealerships are thinking about it like this:

Hmmmm, what's another way to take money from people for doing next to nothing? I know, let's fill their tires with Nitrogen. See, it sounds like nitrous so some people might associate it with going faster. Next we'll have to take a small fact and blow it way out of proportion and we'll be ready to market this to the masses.



Why not fill the tires with Helium? The bouyancy of the tires would reduce road friction, improving both fuel mileage and hillclimbimng performance!!

...but watch out for crosswinds... :P :lol: :idea: :crazy:

Back on subject though…if you guys know anyone that
Paintballs, they use nitrogen as standard now. So if you
know someone that runs a field or has their own home
fill setup, maybe they can hook you up? It’s been years
since I’ve done any paintballing, I don’t know anyone
with the gear anymore…


ACtually paintballers call it nitrogen but most are filled from scuba tanks which are filled with nothing more than compressed air. It is up at 2000-3000 psi. If you dig into the research they call it nitrogen because it is *Mostly* nitrogen, just like regular air.


I am sure some fields go to the trouble to actually get nitrogen, but 95% are going to use compressed air.

I don't know the "facts" about gasses but my understanding is one of the main factors of Nitrogen over compressed air is the ablilty to maintain itself in the tire with less chance of psi loss.

One of the main worries about tires is running on too low of air. There are plenty of people out there who never ever check their air pressure (picture the elderly lady who lives by herself).

safety nitrogen might be a better deal. $40 for safety is low.

keep in mind for every 10 degrees of temp change you lose/gain 1 psi. a person checks there tire pressure in the summer when it is 90degrees and come winter time at 20 there could be up to a 7 psi difference.

this is an issue

Mr. Wizard time here kiddies... Now get your parents permission before doing the following experiment. :pray:
Fill two ballons, one with Dry air and one with Dry nitrogen,to the same size and tie them off. :lalala:

Test 1:<Weight Savings> There may be some weight savings but at the pressures and amounts we are talking about it is negligible. Weigh the two above mentioned ballons.

Test 2: <Pressure Change> Dry Air and Dry Nitrogen will experence pressure changes at the same rate. place the two balloons in the freezer for an hour, note the size, leave out for an hour, note the size, the sizes should remain similar in both conditions :tap:

Test 3: <Pressure Retention> A tire that will 'leak' regular air will 'leak' nitrogen at the same rate. Leave the two ballons alone for a couple days. compare sizes.

I read somewhere that on average a tire loses 1-2 PSI a month, so everyone should be checking tire pressures at least that often (some of us do it on a weekly basis).

No, you're correct about the moisture but that's not going to effect anything as far as normal driving goes. I would be shocked if it could muster a .5 psi change.

I'm just saying this is a waste of money. Dealerships are thinking about it like this:

Hmmmm, what's another way to take money from people for doing next to nothing? I know, let's fill their tires with Nitrogen. See, it sounds like nitrous so some people might associate it with going faster. Next we'll have to take a small fact and blow it way out of proportion and we'll be ready to market this to the masses.



Why not fill the tires with Helium? The bouyancy of the tires would reduce road friction, improving both fuel mileage and hillclimbimng performance!!

...but watch out for crosswinds... :P :lol: :idea: :crazy:

The buoyancy of helium wouldn't make much difference, but think of the kewl factor!

The other problem with helium is that it has the smallest atomic size of all the gases. It will leak out faster than air, nitrogen, or whatever. Think about how fast a latex helium balloon loses its gas, as it diffuses right through the rubber!

Now what about hydrogen? Large atomic size (it's on the far left end of the periodic table), diatomic, and very low density. Perfect for filling tires except for that little "Hindenberg factor"! :)