Inflate Your Tires With Nitrogen

[SVOboy]

<a href=http://ezinearticles.com/?Save-Money-and-Gas,-Fill-Your-Tires-with-Nitrogen&id=75424 target=_blank>Nitrogen Article</a>

So, I'm not entirely sure why nitrogen is better than air, other than it doesn't leak as much, or why it would give better mileage, but mehbe someone could figure this out and explain it to me? Also, where do one go to fill their tires with nitrogen? I don't know many nitrogen stations around...Seems like a good thing to test though, I must say.

[diamondlarry]

I think I heard once that nitrogen is used because it isn't affected by temperature like air is. Your tire pressure doesn't go up when you drive. If that's true, it would sure make testing for benefits of increased tire inflation on mpgs. I've never heard where you get the nitrogen though.

[dfoxengr]

correct, temp doesnt affect N2 as much as oxygen, so when your tires warm up by driving, or the weather changes, then it doesnt expand or contract as badly. this is why it is used in gas-shocks also.

the affective cost though probably isnt worth it and if you chek your pressure regularly then the the mileage is negligable.

[Paul Osborne]

Years ago before the EPA banned purging, I used to top my leaky tires off with refrigerant 22. Having a 30lb drum of freon and a set of gauges in the garage was handy.

Now, doesn't that just beat all?

:-)

Paul O

[rh77]

So, it's time to resurrect an old thread. On my last car, Nitrogen-fill was standard on any new tire purchase. So, right now, I'm sitting in Indy watching TV, and a local tire store advertises that, "We fill all of our tires with Nitrogen, so you get better gas mileage!" I thought, OK, you're going to explain this right? The spokesmodel said, "Nitrogen is resistant to heating up as you drive, keeping your tires cooler, and you get better mileage!"

OK -- I understand that warmer tires yield better traction in cornering due to higher friction, but does this carry-over into straight-line driving? Second, it's basically a given that tire over-inflation gives you better economy. So my hypothesis is that 1) It's a gimmick to charge a little more, and 2) SUV drivers' underinflated tires may stay cooler and not blow-out.

For me, I'll stick with "air" and let the tires heat-up and increase in pressure as I drive to increase FE. Isn't the air around us 70-some% Nitrogen anyways?

RH77

[tomauto]

Air is 78% nitrogen. It couldn't be much better with all nitrogen, people just have a real problem with keeping their tires inflated. I see tires low all the time, I want to make a sign saying your tires are low! --Many people wouldn't even know what to do. I talked to a few people at school and I had one person who didn't check their pressure in 9 months because their car was ''new''...

[zpiloto]

I think the only way you would get better mileage is because Nitrogen doesn't leak down as fast thus the folks that never check their pressure will not lose as much air between oil changes when they have Jiffy lube check it.

I checked my tires after each leg of my 26 mile commute the temps were 89 and 93 and the increase in pressure was only 4 PSI.

[Ryland]

I tend to agree that nitrogen shouldn't help with mileage all that much, doesn't tire presure go up with highway driving/hot tires?
however in theory nitrogen filled tires should last longer due to the lack of 02 and water vapor in the tire, reducing rust in steel rims, and tire rot in all tubes and tires, this would be most affective in bicycle tires, motorcycle tires, and tires on vehicles that tend to sit.

you can get your very own tank of nitrogen from brew suply stores.

[zpiloto]

Originally Posted by theclencher

http://www.sptimes.com/2005/09/28/Ta...our_tire.shtml

I think that sums it up fairly well.

I used to work as a lineman at an airport FBO and we used nitrogen in the rental aircraft tires. Supposedly it was for the safety aspect of it.

They use nitrogen in planes for several reason: Less air loss during temperature extremes, keeps moisture out for rust, you don't have to worry about it freezing when at altitude, and to keep the heat down when the tires go from 0 MPH up over 130 MPH or more when landing and taking off. Not to mention the incredible heat generated by braking. It's really amazing when you think about the abuse they receive and how much weight they support.

[AlexK]

This is my first post here... I had to comment on this.

I cannot see how nitrogen in tires would keep them significantly cooler than air. The specific heat of nitrogen is about 30% higher than air, but there simply isn't enough mass there to really make a difference. The mass of the tire and rim dominates the situation. Could it be viscous heating of the gas due to tire rotation? I think the gas would simply rotate with the tire and not have much viscous dissipation.

Also, how can nitrogen leak so much more slowly than air? Air is 78% nitrogen, so is the oyxgen leaking out? If so, eventually we would be left with just nitrogen in our tires anyway, as the oxygen is leaking out and leaving the nitrogen behind.

Nitrogen rises in pressure when heated the same as air does (neglecting very tiny differences to to gas compressibility, on the order of 0.05%). Most all gasses behave like ideal gasses at low pressure and temperature (much less than critical pressure/temperature).

I could see a benefit with corrosion but honestly, when was the last time a rim rusted away from the inside out?

I say it's a scam.

Before you say I don't know what I'm talking about, I'm an engineer in the R&D department of a company which makes instruments to measure gas flow. I know a little bit about gasses. I also have a masters degree in mechanical engineering (heat transfer and fluid mechanics). I do like to learn new things though, if I'm wrong please explain.

[SVOboy]

Woo, hey there alex! Strong words always speak the loudest!

Anyway, feel free to introduce yourself in the intro forum and thanks for stopping by our forum here to share your expertise.

[rh77]

Originally Posted by zpiloto

They use nitrogen in planes for several reason: Less air loss during temperature extremes, keeps moisture out for rust, you don't have to worry about it freezing when at altitude, and to keep the heat down when the tires go from 0 MPH up over 130 MPH or more when landing and taking off. Not to mention the incredible heat generated by braking. It's really amazing when you think about the abuse they receive and how much weight they support.

I can see the use of something with even a slight increase in safety, especially when it comes to tires in the aircraft industry. I'm not sure if it's just me, but I've noticed that when possible, commercial pilots resist reverse engine thrust and only use the brakes on landing, consequently using the whole runway. Is fuel cheaper than brake linings? They are doing this even in non-noise reduction areas and on large airliners (MD-80s on American specifically). This has to heat up the whole assembly tremendously.

Back to cars, I'm tending to agree with AlexK on the physical properties of Nitrogen and atmospheric gas makeup, and that it's probably all lights-and-mirrors in the auto industry.

RH77

--Oh, and welcome to GS AlexK!

[Ted Hart]

Originally Posted by AlexK

This is my first post here... I had to comment on this.

I cannot see how nitrogen in tires would keep them significantly cooler than air. The specific heat of nitrogen is about 30% higher than air, but there simply isn't enough mass there to really make a difference. The mass of the tire and rim dominates the situation. Could it be viscous heating of the gas due to tire rotation? I think the gas would simply rotate with the tire and not have much viscous dissipation.

Also, how can nitrogen leak so much more slowly than air? Air is 78% nitrogen, so is the oyxgen leaking out? If so, eventually we would be left with just nitrogen in our tires anyway, as the oxygen is leaking out and leaving the nitrogen behind.

Nitrogen rises in pressure when heated the same as air does (neglecting very tiny differences to to gas compressibility, on the order of 0.05%). Most all gasses behave like ideal gasses at low pressure and temperature (much less than critical pressure/temperature).

I could see a benefit with corrosion but honestly, when was the last time a rim rusted away from the inside out?

I say it's a scam.

Before you say I don't know what I'm talking about, I'm an engineer in the R&D department of a company which makes instruments to measure gas flow. I know a little bit about gasses. I also have a masters degree in mechanical engineering (heat transfer and fluid mechanics). I do like to learn new things though, if I'm wrong please explain.

Right on, Alex! The Ideal gas law sez: All gases behave the same way"...right? I believe some NASCAR types started this nonsense (they're good at straw-grabbing!). -Ted Hart

[Brian D.]

Kill two birds with one stone (sorry PETA):

Inflate them with Helium & reduce your curb weight!!

lol, sorry, I had to say it.

[JanGeo]

Nitrogen helps prevent combustion and is very dry so you get rid of the freezing moisture problem in aircraft. In a car I can't see much difference but I did have the inside of a rim on my BMW motorcycle get all chewed up from liquid tire balancer. Nitrogen is a little less dense than oxygen atomic weight Nitrogen 14.00674 vs Oxygen 15.9994 in the periodic table.

[Ted Hart]

Originally Posted by Brian D.

Kill two birds with one stone (sorry PETA):

Inflate them with Helium & reduce your curb weight!!

lol, sorry, I had to say it.

Ah! Always the sexist (did I spell this right?) in our midst! The ladies out there might want to inflate their tires with Shelium! After all, the ladies watch their weight, curb & otherwise! -Ted Hart

[Gary Palmer]

Yes, but does Shelium have the same weight compensating qualities?