What Pressure Should Be Run In Tires (Nitrogen?)

[DOCTORBILL]

I am starting this new thread about the best pressure to run in your tires and
whether or not Nitrogen should be used instead of air?

In my Thread "The Flight of The Phoenix" a side conversation got started
about this tire pressure business and I'd like for others to see it also.

For a preamble, visit "The Flight of The Phoenix" to see what has been said
and then continue with the discussion here - PLEASE!

Personally, I will keep to AIR and forget about the Nitrogen thing.....I suspect
my tires will wear out before this discussion does!

As to pressure - Hell! Who knows!? Yikes! Such opinionated folks!

Personally, I have inflated my snow tires to 40 psi (44 max) in an effort to
become a middle of the roader (pun?).

Have at it guys!
Marquis of Queensbury rules!
No punching below the belt.
No biting off ears.
No poking in the eye!
No spitting!

DoctorBill

[lilrogue78]

Is kicking allowed? :P
i will stick with the doc I like my AIR personaly nitrogen just isnt made for a car tire Heck air has been used seince the day the rubber tire was made so ya know what? it will keep being used too

[JustSayGo]

Air is 79% nitrogen. Your tires are already filled with more nitrogen than anything else. What you are really saying is you will stick with the 21% oxygen and the moisture that clings to the oxygen in your tires. Moisture is more molecules of oxygen and hydrogen. These are the culprits that have such volatile molecular kinetic energy that cause the air pressure in a tire to change as temperature rises and falls.

Nitrogen molecules are fatter and much more stable than oxygen or hydrogen molecules. So tires don't leak down as quickly as air and stay at what ever pressure they are set at through every season without maintenance. You can always add air if inflation is necessary.

You can stick with air or wooden spoke wheels with steel bands.

Properly inflated tires are safer and last more miles. Tire manufactures are experimenting with using little nitrogen filled capsules to inflate tires. I don't know how or if those tires will ever have pressure adjusted... or if they will ever make it to market.

Aircraft tires have to be filled with nitrogen to maintain pressures as altitude and temperatures drastically change. Automobile tires can share some of the same benefits.

[DOCTORBILL]

That is all 'fine and dandy', JSG.....

I will use Nitrogen when it doesn't cost $10 per tire to fill them! Or even $1 per
tire!

I have gotten along just fine for the 45 years I have driven automobiles and the
other 15 that I rode bicycles with air in the tires as a kid !

You can take science a bit too far.....actually way too far.

Like the people who pick thru the grocery shelves worrying over the Salt Content
of everything they eat...or the Fat Content of each item.

Aircraft - great. Military - they love to spend money.
I wonder what the military says it costs to fill just one F-16 Tire? $1,000 per tire?!

If someone comes up with a molecular filter that separates the Oxygen
(95% of Nitrogen's size) from Nitrogen that I can put on my Air Compressor for
$5, I'd be glad to put nitrogen in all my tires.

If you live in Florida and fill your tires on a humid day...tisk, tisk! Who cares?
The temp stays above 32° F anyway - always!

If you live in Arizona and fill your tires, water is not a problem ever!

If water concerns anyone - go obtain a dryer cartridge with Calcium Chloride
drying agent in it and place it on the Air Compressor's intake port.

Most water comes out the bottom of my Air Compressor anyway when I open
the tank to decompress it when I'm done using it.

Tempest in a teapot.....Sales gimmick.

"Never give a sucker an even break!"..........W.C.Fields


DoctorBill

[JustSayGo]

No sales gimmick because there is no sales. Tires cost the same either way. They don't make folks who are nitrogen adverse use nitrogen. The nitrogen is free when you buy your tires at Costco. I guess the sales gimmick is extra service at no extra cost. Discount tire has also used nitrogen at many stores as a test.

The air compressors look pretty much the same. I think they heat the air enough to burn up the oxygen and remove the moisture. Not just military, every commercial airline. Tell me more about why you write that nitrogen is expensive.

I never suggested you use nitrogen or that you fill your tires to max inflation. I wrote that you should pick up the nitrogen pamphlet from the Costco tire center to understand the advantages of using nitrogen in tires, which was related to your tires loosing pressure from sitting for so long. I am mostly amazed at how my tires still have the same pressure more than a year after being installed. Your tire pressures are fine. How often do you check your tire pressure and re-inflate?

I have found the same observation as fritz14 mentioned to be true. Cars usually corner better when tires are inflated to max... especially when the load more than doubles as the inside tires leave the ground.

Most condensation is removed when you drain your air compressor tank. The air that goes into the hose is on top of the tank. The air we breath has moisture in it, even in Phoenix on a dry day. According to the info from the tire manufactures and the compressor people the moisture connected to oxygen is what causes the change in pressure as temperature changes. I thought you would be interested from a chemistry stand point

http://www.branick.com/pdf/CostcoPressRelease.pdf

Just listen to Willard. Willard says Costco will fill your Korean knock-off tires for nothing just because you are a member. Explain the sales gimmick or disadvantage that I am not seeing.

http://www.n2revolution.com/

Check out the picture of the KLM aircraft at the end. I have stood at the fence directly under a 747 while aircraft land and take off. I don't need to do it again. Seen kids get blown across the road from the jet wash during takeoff. An Air France 747 tail touched the fence while landing during my first visit. Didn't see it but a lot of people were stranded until it was certified or repaired. What a great place, topless girls drink for free.

[DOCTORBILL]

I called it a "sales gimmick" because when I got onto the Internet (Google) during
our past conversation on this subject, I saw places advertising Nitrogen Tire
Filling for $10 per tire! I wish now I had referenced them....

If COSTCO fills their new tires sold with N2 at no charge - GREAT!

Question - how do they remove the resident AIR before filling with N2 ?

You would have to fill, "empty" (which cannot be done!) and refill probably 5 to
10 times to get the O2 out of there...

Dilution calculations.... 1 vol air (20% O2) + 1 vol N2 - result = 10% O2
Empty - do it again = 5% O2 do it again 2.5% O2

About 5 times to get to 1% O2.

What percent of O2 is acceptable?

I'll bet the pressure drop in any tire is not O2 going thru the rubber, either...

O2 is 95% the molecular width of N2. I looked it up in the Handbook of Chemistry
and Physics 43rd Edition.

Actually, water is smaller by mass than either O2 or N2.

O2 is 32 grams/mole. N2 is 28 grams/mole. Water is 18 grams/mole.

So, if anything is going to diffuse thru something, water would do it faster.

Except water is a bent molecule and is Polar as hell. So...who knows?

You Nitrogen guys keep doing your thing....

Us old Horse and Buggy whip guys will drive along smiling and listening to
Credence Clearwater Revival and know that air is available just up the road at
the local gas station....or in our trunk via the old standby tire pump....

and in our simple-minded ignorance, we will merrily motor on and replace our
worn out tires at the appointed time and place.

DoctorBill

[JustSayGo]

The tire machines run off of the nitrogen and blow most of the air out from inside the tire. I notice they claim (some sort of guess) to wind up with 98% nitrogen after inflation.

Wherever the air pressure leaks out, I have observed that air leaks 6 times faster than nitrogen is sill a conservative claim.

[sbiddle]

I have a MIG welding rig along with a bottle of 75% Argon/ 25% CO2 shielding gas. While this gas is expensive to buy, since I already have it, what would be wrong with using it to fill my tires? The atomic number of Argon is higher than Nitrogen, so I assume it's a bigger molecule and won't leak out. C02 should be bigger than N2 as well.

[DOCTORBILL]

I would not run Argon in my tires as this is a "Noble Gas".

Noble gases are single atoms, not molecules.

As a result they are smaller. That is why Helium balloons go flat so fast.

The Helium ( the first Noble Gas) goes right thru the rubber or plastic.

Argon, of course, is bigger in diameter than Helium, but all Noble Gases are very
inert and can travel between rubber molecules w/o hindrance.



That is why RADON (the last Noble Gas on the Periodic Chart) gets into
basements so easily - it is a Radioactive Noble Gas that decays into
radioactive Polonium Metal! It passes thru concrete w/o hindrance!

Nitrogen and Oxygen are diatomic and thus larger.

I was wondering if Carbon Dioxide would be a good filling agent !

It is 44 grams/mole and thus a large, linear, non-polar molecule.



It is dog, dirt cheap also!

What say you, JustSayGo?

To Carbon Dioxide or not to Carbon Dioxide?

What about Methane, Propane or even Butane in one's tires? Big Molecules.

Who cares if they are flammable or not! One's tires are sealed up anyway!

You could fill your tires with a Propane ( Boiling Point -42° F) Torch Bottle purchased in any store for $3...

DoctorBill

[sbiddle]

Thanks for the chem refresher Dr Bill. Propane sounds like a good choise. I agree that the flammability would'nt be a big issue since you're not talking about a lot of volume.