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Author Topic: Nitrogen in tires?  (Read 3497 times)
johns4104s
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« on: April 22, 2010, 07:01:11 PM »

Is there any advantage to put nitrogen in the toad or coach tires? Better ride? Just what are the advantages?

Thanks

John
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cody
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« Reply #1 on: April 22, 2010, 07:04:28 PM »

My understanding of it is the profit is greater for the dealer, the claims made don't seem to add up to any great advantage over just air.
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« Reply #2 on: April 22, 2010, 07:17:37 PM »

John,

The primary advantage is to the guy who sells it. Since air is mostly nitrogen anyway it is just a scam.

You also run the risk, although very slight, of blowing your tire out with the very high pressures in nitrogen tanks.
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« Reply #3 on: April 22, 2010, 07:51:05 PM »

John, I don't know for sure if works or not but Sonja's Lexus has Nitrogen when I bought the tires 5 years Les Schwab did it for free and last week at Costco when she had the tires checked they had only lost 3 to 4 lbs in 5 years.
Fwiw I think it works in the AZ heat as her car sits for months and the tires never bounces (could be the tire) watching Schwab do it they mounted the tire then let the air out and pulled a small vacuum on the tire then the nitrogen but paying 5 or 10 bucks a wheel I would go with the air


good luck
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« Reply #4 on: April 22, 2010, 08:13:34 PM »

Okay, I have to chime in here!

I have used Nitrogen in my race car's tires for years.

Here's my portable set up



Note my Schrader (sp?) valve on the end of the hose!  I used the tank to fill the inside rear tire on my bus after having new tires installed and getting a faulty valve stem.  The shop installed a new one free of charge, but that nitrogen tank filled that tire from 40 to 90 psi numerous times!

On air, I get 10psi rise in tire air pressure on the track in three laps.  With nitrogen, only 4 psi!

I use it in my car trailer tires.  I've never had a blowout since.

The benefits are true.  The cost??? Who knows.  It's all part of the racing budget. LOL!

« Last Edit: April 22, 2010, 08:22:19 PM by OneLapper » Logged

OneLapper
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« Reply #5 on: April 22, 2010, 08:18:08 PM »

John, I don't know for sure if works or not but Sonja's Lexus has Nitrogen when I bought the tires 5 years Les Schwab did it for free and last week at Costco when she had the tires checked they had only lost 3 to 4 lbs in 5 years.
Fwiw I think it works in the AZ heat as her car sits for months and the tires never bounces (could be the tire) watching Schwab do it they mounted the tire then let the air out and pulled a small vacuum on the tire then the nitrogen but paying 5 or 10 bucks a wheel I would go with the air


good luck

Nitrogen molecules are larger than O2, so they do not leak out of tires as quickly.  Also, there is zero humidity in nitrogen, a huge advantage to tire life. Tires do not like humidity inside them! Steam expands!!!!!
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« Reply #6 on: April 22, 2010, 08:43:46 PM »

Also, there is no moisture (basically) in nitrogen so the steel wheel doesn't rust. I don't use it in the big trucks/trailers, but I do on the motorcycles...primarily to limit rust/corrosion on the wheels and they hold air pressure longer.

With the regulator, I don't think that you would over-inflate a tire because the air hose/chuck would probably fail before the tire was aired up. Just my opinion.

Shops that use nitrogen generally use a green valve cap.
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Dreamscape
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« Reply #7 on: April 22, 2010, 09:02:18 PM »

Nitrogen has been used for airing up tires for many years, ask the racers. It also doens't expand like oxygen does. I haven't used it, only what friends have said.

Most shops will have it available, they use green caps on the stems to let you know.
« Last Edit: April 22, 2010, 09:09:24 PM by Dreamscape » Logged

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« Reply #8 on: April 22, 2010, 09:17:10 PM »

Tire mfr.s have tables for determining the correct tire pressure by loading.  OK, so duh!  BUT, if nitrogen doesn't have the same ex;pansion characteristics as "air" then you will be off in the "heated under load" end of that equation.

Way back it was common to get a little water out of the compresed air hose.  Now, that never happens today...right?  Water, over time, dry rots tires....I think.  I know that 2 messes with it, for sure.   I think the question is "how much"?  Both in terms of cost and degree.

Scuba air is dry and a little tiny bottle will fill a lot of tires and shoot a gazillion pellets down range.  See, if you are down a hundred feet, well, wet air defeats the purpose. Huh Roll Eyes Shocked Smiley

John....I'm pretty sure
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« Reply #9 on: April 22, 2010, 09:28:53 PM »

From the truck trade press, there are fleets that are running nitrogen, and their tire programs are showing that it works. More consistant pressures, less leakage, good casings. Oxygen is needed for corrosion of both metals and rubber.

Yes, there are lots of dealers using nitrogen as a profit centre, do you blame them?
If folks will pay, that's how capitalism works!

However, for busnut use, with our really low mileage, and that most of us age tires out, the cost/benefit is likely a crap shoot.

Those who are likely to encounter extremes in temp, high and low, might have some benefit to nitrogen use?

happy coaching!
buswarrior

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Sean
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« Reply #10 on: April 23, 2010, 12:37:07 AM »

... It also doens't expand like oxygen does. ...


Umm, all gases expand exactly the same way.  The equation is PV=nRT, also called the ideal gas law.

If the absolute temperature goes up 10%, then either the pressure or volume (actually, the product of the two) must also rise 10% -- it doesn't matter whether the gas is nitrogen, oxygen, helium, or even steam.

There are exceptions to this rule at extreme limits, when gases are said to be "non-ideal," but that does not apply to air versus nitrogen in tires.

Note that any liquid component will change the dynamic.  So if you have entrained water in the air supply, then, yes, as the tire heats, the water will vaporize into steam, and that will increase the pressure (or volume) by a greater percentage.  This is one reason why the air supply should be perfectly dry for airing tires.

... On air, I get 10psi rise in tire air pressure on the track in three laps.  With nitrogen, only 4 psi! ...


Then you had water in your air supply.  See above.

Nitrogen molecules are larger than O2, so they do not leak out of tires as quickly.


OK, this part is true -- but just barely.  The difference in size is minute.  Also, if this claimed benefit is really operating at any significant level, then, theoretically, your tires would be mostly full of nitrogen after a few top-ups anyway.  Air is 80% nitrogen to begin with, so after first airing up the tire, it will be 80% nitrogen.  Now let's say that all of the oxygen leaks out, and you find your tire pressure to be 20% low.  You fill the tire back up with air -- now you have 96% nitrogen and 4% oxygen.  If that 4% also leaks out, when you top up again, you'll have 99.2% nitrogen, and only .8% oxygen.  Etc.

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Also, there is zero humidity in nitrogen, a huge advantage to tire life. Tires do not like humidity inside them!


Well, OK, but you can also have 0% humidity in "air" too.  Note that nitrogen is made by processing air, not from some other magic process.  That processing removes the  oxygen as well as other trace gasses, and, of course, the moisture.  But it's not perfect -- some trace gasses and even some water vapor remains.  It is certainly easier and less expensive, though, to just remove the water than to remove everything else, too.

Quote
Steam expands!!!!!


Uhh, yes, exactly the same way that nitrogen does.  Again, see "ideal gas law" above.  Steam is a gas, which is not to be confused with liquid water.  Liquid water, as I wrote above, can be entrained in the air supply and can vaporize inside the tire, increasing the pressure.  Perhaps this is what you are thinking of.

... Oxygen is needed for corrosion of both metals and rubber. ...


Buswarrior is correct.  This is really the only significant advantage to using nitrogen over (100% dry) air -- oxygen, well, "oxidizes."  Oxidation of the rubber ultimately weakens it.

That said, the likelihood that oxidation on the inside of the tire can have a measurable impact on the life of a heavy-duty tire is very small.  First off, the tire is exposed to oxygen for its entire life up to the point where it is mounted and filled, and so there is already an oxidized layer.  That layer actually inhibits most further oxidation.  As the tire flexes, there will be some additional oxidation.  But most tires will wear out long before this oxidation can become a factor in casing failure.

I personally believe that fleet programs seeing a measurable difference using nitrogen fills are actually reaping the benefits of having a consistent fill source.  By mandating nitrogen fill, you are precluding the driver from filling his tires at some crappy truck island that might be loaded with moisture.

The single largest cause of tire failure is under-inflation.  Take the money you would spend on nitrogen fills and invest in a good tire gauge, and use it before every trip -- you will be ahead of the game.  And you'll compensate for any of those sneaky oxygen molecules that permeated through the casing.

FWIW, JMO, YMMV, etc. etc.

-Sean
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jackhartjr
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« Reply #11 on: April 23, 2010, 04:57:13 AM »

The single best reason to use nitrogen is this.
If you get a nail, screw, etc in a tire that you don't see...and if it is not causing a leak...with nitrogen, you will not get the rust which eventually causes the steel belts to rust, then you get the tire failure.  An old trucker taught me that.
The fleets that use nitrogen are saving big bucks.  Especially if they run in hot climates.  Much less tire failures due to heat.

Sean is right...underinflation kills more tires that anything!
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« Reply #12 on: April 23, 2010, 07:15:15 AM »

One lapper, you probably know this, how and where you store your tires.....moisture collects.....on dirt we install reliefs and purge the tire for maybe 10 minutes or longer depending on the humidity, the increase is definately less than what you are seeing........we've used this for about 10 years or longer, with excellant results, chasing the track and tire moisture is the battle!  
« Last Edit: April 23, 2010, 10:03:56 AM by muddog16 » Logged

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« Reply #13 on: April 23, 2010, 09:29:20 AM »

Wonder why the military and the airlines use nitrogen to fill aircraft tires?  Probably just throwing away money!  Regards Johyn L
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rgwilliams
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« Reply #14 on: April 23, 2010, 09:57:35 AM »

Fire or explosion safety.  Same reason they use it in the oleos (shocks) in the landing gear.
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Tony LEE
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« Reply #15 on: April 23, 2010, 10:18:19 AM »

From the Goodyear Tyre Manual

Quote
Over the years, nitrogen inflation has
been proposed for various types of tires,
including large earthmover tires down
through small passenger tires. At the
present time, Goodyear endorses nitrogen
inflation for certain sizes of earthmover
tires used in particular applications, and
has issued detailed instructions for these
tires. Anyone concerned with applying
or maintaining earthmover tires should
be aware of the Goodyear Service
Department Bulletins and Off-the-Road
Tire Training Manuals that contain details
of nitrogen inflation recommendations
for these large off-the-road tires.
The issue of nitrogen inflation for
over-the-road truck tires is not quite so
clear. Various performance improvements
have been claimed, including better
treadwear, casing durability, and reduced
susceptibility to tire fires.
Although little actual controlled test
data exists, a summary of Goodyear’s
experience with nitrogen inflation for
truck tires is the basis for the following
comments. Treadwear appears to be
affected negligibly by the tire inflation
medium. Specifically, there is little, if
any, tread life change to be expected by
using nitrogen inflation compared to
normal air. So far as casing durability
and retreadability are concerned, the
primary criteria is to avoid moisture in
whatever inflation medium is used. To
this end, we strongly encourage proper
selection of compressor equipment,
air-line routing, the use of air dryers,
and other good shop practices to avoid
the introduction of moisture into high
pressure air used for both initial tire
inflation and make-up air. Again, we
know of no significantly improved casing
durability or retread durability performance
to be expected from nitrogen inflation in
over-the-road truck tires.
Reduced rim or wheel corrosion has
also been cited as an advantage of nitrogen
inflation. However, corrosion is primarily
the result of excessive moisture introduced
by air that has not been properly dried,
rather than a direct result of air versus
nitrogen inflation.
An additional concern is that past
studies have shown that a very small
percentage of non-nitrogen make-up
inflation significantly contaminates the
contained nitrogen atmosphere within a
tire. In other words, if any benefits are
to accrue from nitrogen inflation, it is
essential that virtually all make-up inflation
throughout the life of the tire/wheel
assembly be diligently controlled to assure
a near 100 percent nitrogen environment.
A final issue is that of insuring against
tire fires and/or self-ignition of tires
resulting from excessive heat. For truck
tires, this concern has been greatly
reduced in recent years, primarily
because of the changes from bias to
radial tires and from tube-type to tubeless
tires. The tubeless radial tire is simply
much less susceptible to a tire fire than
a bias tube-type design. This is partly
because of the simplicity of the tubeless
design (i.e. no separate tube and flap to
create heat from rubbing or internal
friction when the assembly deflates or
runs severely underinflated or overloaded),
and partly because steel radial truck tires
require higher temperatures for a fire to
start than their fabric-reinforced bias-ply
counterparts.
In summary, nitrogen inflation
appears to have significant advantages
for certain sizes and applications of large
off-road tires, especially those operating
in extremely high load or speed
environments. However, nitrogen
inflation appears to have quite small,
perhaps insignificant, advantages for
over-the-road truck tires.
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« Reply #16 on: April 23, 2010, 10:20:30 AM »

From the C-130 etc use it in the Nitrogen/Hyd landing gear, also artillery use it in the recoil assy for the gun tubes, the M-1 Abrams recoil assembly can use up to 2,300 psi depending the set up called for(fine tuning), which can mean the difference in spilling your coffee (never fun Angry)when you hit the trigger  Grin Grin
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« Reply #17 on: April 23, 2010, 06:15:00 PM »

Aircraft use nitrogen for the simple reason that  they go from one atmospheric pressure extreme to another in a matter of minutes and in struts dryness is also very important to prevent corrosion. Pressures in aircraft struts are extreme, thousands of psi, even in smaller aircraft.

We don't usually have these conditions in bus tires!!
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« Reply #18 on: April 24, 2010, 01:26:56 PM »

"Aircraft use nitrogen for the simple reason that  they go from one atmospheric pressure extreme to another in a matter of minutes and in struts dryness is also very important to prevent corrosion. Pressures in aircraft struts are extreme, thousands of psi, even in smaller aircraft."

Gus

You are correct about the extremes of pressure and lack of corrosion and our buses aren't subjected to these conditions.  However, nitrogen gas, while not a noble gas, but fairly inert, will not promote combustion.  The extreme pressures in a 747 strut on touchdown, causing severe compression of the gas, are more than ample to ignite the hydraulic fluid in the strut by dieseling- extreme pressure=a lot of heat- if there was oxygen(a constituent of compressed air) present in the strut.  The pressures in a diesel cylinder are only around 600psi, the strut at rest before a 1.5G impact is around 1500psi.  As for the nitrogen in aircraft tires, check the probable cause of this disaster in the 3rd last line of the Narrative.
http://aviation-safety.net/database/record.php?id=19860331-1&lang=en

Rob
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« Reply #19 on: April 24, 2010, 06:38:56 PM »

Rob,

I never really thought much about the fire aspect but this probably isn't a problem in bus tires.

I'm sure you're right, I hadn't thought in terms of 747s but I know my little ole Navion had strut pressures in the thousands of psi on full compression. I always aired it up at full extension which was still around 250 psi as I remember.

My son works on 747s and 777s at Everett, WA.
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Ed Hackenbruch
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« Reply #20 on: April 25, 2010, 08:51:50 AM »

I use Helium in my tires, make the bus lighter so i get better mileage. Smiley You can also use laughing gas if you want to keep your tires happy. Grin
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« Reply #21 on: April 25, 2010, 03:49:41 PM »

Ed, I think you're on to something here!

However, be careful, you may have inhaled some of those gases!!!
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