Tires with Nitrogen

[Bill 340]

well I know this will cause controversy but its what I DID and these are my results... This week I had a young man come to my home with a van equipped with a Complete nitrogen system he pumped the air from my VAN tires, he then replaced it with nitrogen, Well the next day I had to travel I-4 to clearwater fl, and back of course, the van never rode so quiet, I was on black top, concrete and plain rough road, very quiet compared to past road noise, Next day to Orlando and back again less road noise, now they tell you that it helps increase fuel mileage, Maybe it does maybe not didn't check that yet, Very satisfied with what I have found. SO I called him today and convinced him to come to the Arcadia rally, he only has one day he can make it, and that is Dec 30, so if anyone wants to make sure he will have time to do their unit, I am sure he would appreciate a heads up, so he can judge his time, thanks and we will see you in Arcadia, His name and number is Nitro Tire--Chad Smith- 863 412-0177

[lostagain]

Why would nitrogen filled tires be any quieter than air filled tires?

So now when a tire is low, you need to be looking for nitrogen. So much easier, and cheaper to stick with regular old air.

JC

[luvrbus]

JC it does help the smaller tires I tried on the 12rx22.5 on the bus I could not tell any difference except I had to pay till I got my own bottle to top the tires off I still use it on the car,Cosco does that at a good price real popular here in the desert in the heat the tire pressure won't vary   

good luck

[lostagain]

Yea, but what is in nitrogen that isn't in air that would make a tire run quieter? The only thing I understand is that nitrogen doesn't leak out as much as air, so the pressure stays more constant.

JC

[Oonrahnjay]

Yea, but what is in nitrogen that isn't in air that would make a tire run quieter? The only thing I understand is that nitrogen doesn't leak out as much as air, so the pressure stays more constant.  JC   

     Yeah, JC - you just don't understand.  I've been breathing 79% nitrogen for years.  The guy that sold me the compressor and mask told me that I'd be a lot healthier.  And he's right.  I've been healthy!  When people are selling you stuff, that makes them experts and you should listen to experts!

[Iceni John]

Nitrogen is to tires what Oxygen Bars are to hip impressionable folk who love anything new.

Seriously though (!), is it the lack of moisture, or the lack of oxygen, or what, that makes any claimed difference?   Costco put nitrogen in my car's new tires, but I can't say what difference there is to regular air because they are new tires, with different handling/ride/noise/etc than my old worn-out tires.   Is there any scientific testing to validate the claims, or is it just subjective feelings and hearsay?   Until I see hard irrefutable proof one way or another, it's just so much hot air to me (so to speak).

Besides, as Bruce says, even air-filled tires are 79% nitrogen anyway.

John

[Depewtee]

The United States National Highway and Traffic Administration released a report in March of 2009 on this subject (see attachment Oops!  File size is too large, link to the .pdf here).  In brief, using nitrogen allows the tire to maintain a more steady air pressure, thus theoretically providing increased fuel mileage and less tire wear.  Additionally, the lack of moisture in nitrogen may result in less tire and wheel degradation. No mention of ride quality.

Brian S.

[JackConrad]

Nitrogen molecules are larger than oxgen molocules and less suceptable to leakage. NASCAR has used nitrogen for years (not sure how many).  I think the biggest difference is the moisture content of typical "gas station" compressed air and (dry) 100% nitrogen. If there is moisture in the air, as the tire heats up, it expands more than 100%  nitrogen. As it expands, it increases the tire pressure.  Watching the PressurePro on our rig, with regular compressed air from my shop compressor, I see about a 5-10 PSI increase in the bus tires and about 3-5 PSI in the toad tires. This is from an ambient starting temp of 50-60 to a running temp of about 120-130.  Jack

[johns4104]

Is nitrogen the only gas that does not expand with heat?

[bobofthenorth]

Is nitrogen the only gas that does not expand with heat?

Every gas expands with heat.

This whole nitrogen in tires thing consumes a lot of internet bandwidth and I'm not going to get into it but every gas expands with heat - that's somebody's rule or law - some of the more eddicated folks on here can tell you which one.

[luvrbus]

With just 8 tires on 1 bus I don't think it would be that great of a saving but a friend that owns Swift in Phoenix he uses Nitrogen he tells me it added 2 to 3-10ths mpg and around 70 to 80 % better tire wear so I wouldn't be too fast to shoot it down he has 4000 18 wheel rigs

I tried to figure his savings for the rigs based on 100,000 miles per year for each rig to much money for me to figure lol I know how Jerry works if it didn't save big bucks he wouldn't waste the money

good luck

[Jeremy]

...that's somebody's rule or law...

Charles' law. (And the increase in pressure which thus occurs in covered by Boyle's Law).

[artvonne]

  They've used Nitrogen in aircraft for decades, not only tires but also pneumatic struts. Several factors exist, as stated very low moisture, another is it is inert so as to lessen the risks of flamability. Being inert it also has zero oxidation effect on rubber seals and o-rings. IIRC, it expands simularly to ambient air, but recall its dry almost zero moisture. Humid air has higher expansion rates than dry air, so nitrogen would therefore have expansion rates similar to dry air. Less humidity may also mean less corrosion....

  Its certainly not going to hurt anything, and it has some good (marginal) benefits over ambient air, just depends on the cost your comfortable paying to use it.

[JackConrad]

Charles law: As temperature increases, pressure OR volume will also increase (see Bolyles law)
Boyles law: pressure and volume are inversly proportional

[bevans6]

I have followed this for years, since nitrogen use in pro racing is ubiquitous, and I have always thought the reason was dry nitrogen did not expand as much as moist air, and you get more stable tire pressures.  So this morning I decided to look into it a bit and found this.  I thought it was interesting enough to cut and paste - it should be easy enough to verify the science.  The short form - moist air actually expands less with increased temperature than nitrogen...  so much for that theory...

Cheers, Brian

nitrogen

Nitrogen inflation (nitrogen filled tyres) is one of those topics that gets discussed in car circles a lot. Some people swear by it, whilst others consider it to be an expensive rip off. So what's the big idea? Well there are two common theories on this.

Theory 1: nitrogen molecules are larger than oxygen molecules so they won't permeate through the rubber of the tyre like oxygen will, and thus you'll never lose pressure over time due to leakage. The fact is any gas will leak out of a tyre if its at a higher pressure than the ambient pressure outside. The only way to stop it is a non-gas-permeable membrane lining the inside of the tyre.
The science bit: Water is about half the size of either nitrogen or oxygen, so it might diffuse out of the tyre faster, but it would have to be much, much faster to make a difference. Tyres can leak 1-2 psi a month at the extreme end of the scale although it's not clear how much of that is by permeation through the rubber, and how much is through microscopic leaks of various sorts. For a racing tyre to lose significant water during its racing lifetime (maybe an hour or so for Formula 1), the permeation rate would have to be hundreds of times faster than oxygen or nitrogen, so that pretty much cancels out the idea that it's the molecule size that makes the difference.

Theory 2: Nitrogen means less water vapour. This is more to do with the thermal properties than anything else. Nitrogen is an inert gas; it doesn't combust or oxidise. The process used to compress nitrogen eliminates water vapor and that's the key to this particular theory. When a tyre heats up under normal use, any water vapour inside it also heats up which causes an increase in tyre pressure. By removing water vapor with a pure nitrogen fill, you're basically going to allow the tyre to stay at a more constant pressure irrespective of temperature over the life of the tyre. In other words, your tyre pressures won't change as you drive.
The science bit: The van der Waals gas equation provides a good estimate for comparing the expansions of oxygen and nitrogen to water. If you compare moist air (20°C, 80% RH) to nitrogen, you'll find that going up as far as 80°C results in the moist air increasing in pressure by about 0.01 psi less per litre volume than nitrogen. Moist air will increase in pressure by 7.253psi whereas nitrogen will increase in pressure by 7.263psi. Even humid air has only a small amount of water in it (about 2 mole % which means about 2% by volume), so that all puts a bit of a blunt tip on the theory that it's the differences in thermal expansion rates that give nitrogen an advantage. In fact it would seem to suggest that damp air is marginally better than nitrogen. Go figure.

So which option is right - smaller molecules, or less water vapour? It would seem neither. A reader of this site had a good thought on the whole nitrogen inflation thing. He wrote: Some racer who did not know the details of chemistry and physics thought that nitrogen would be better because (insert plausible but incorrect science here) and he started using nitrogen. He won some races and word got out that he was using nitrogen in his tyres. Well, it is not expensive to use nitrogen in place of air, so pretty soon everyone was doing it. Hey, until I hear a reason that makes good scientific sense, this explanation seems just as good.

Nitrogen inflation is nothing new - the aerospace world has been doing it for years in aircraft tyres. Racing teams will also often use nitrogen inflation, but largely out of conveience rather than due to any specific performance benefit, which would tend to fit with the armchair science outlined above. Nitrogen is supplied in pressurised tanks, so no other equipment is needed to inflate the tyres - no compressors or generators or anything. Apart from that Nitrogen won't provide fuel in the event of a pit lane fire whereas compressed air tanks would, so there's a safety issue at play in that particular case. (Remember Jos Verstappen's pit lane fire in 1994?)

So does it make a difference to drivers in the real world? Well consider this; The air you breathe is already made up of 78% nitrogen. The composition is completed by 21% oxygen and tiny percentages of argon, carbon dioxide, neon, methane, helium, krypton, hydrogen and xenon. The kit that is used to generate nitrogen for road tyres typically only gets to about 95% purity. To get close to that in your tyres, you'd need to inflate and deflate them several times to purge any remaining oxygen and even then you're only likely to get about 90% pure nitrogen. So under ideal conditions, you're increasing the nitrogen content of the gas in the tyre from 78% to 90%. Given that nitrogen inflation from the average tyre workshop is a one-shot deal (no purging involved) you're more likely to be driving around with 80% pure nitrogen than 90%. That's a 2% difference from bog standard air. On top of that, nitrogen inflation doesn't make your tyres any less prone to damage from road debris and punctures and such. It doesn't make them any stronger, and if you need to top them up and use a regular garage air-line to do it, you've diluted whatever purity of nitrogen was in the tyres right there. For $30 a tyre for nitrogen inflation, do you think that's worth it? For all the alleged benefits of a nitrogen fill, you'd be far better off finding a tyre change place that has a vapour-elimination system in their air compressor. If they can pump up your tyres with dry air, you'll get about the same benefits as you would with a nitrogen inflation but for free.

Read more: http://www.carbibles.com/tyre_bible_pg3.html#ixzz1hGerLq7H