nitrogen or air

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Originally Posted By: Astro14
Sigh...not again...N2...the miracle gas, not subject to the universal gas law PV=nRT, so it never expands and contracts with temperature...and so rare that you have to pay for it...

Oh wait, that's right, regular air is 78% N2...

OK, all sarcasm aside. N2 is both dry and inert. Inert doesn't really matter in car tires, though it might in airplanes. Dry does matter, but I just wait for a dry day and fill my tires from my compressor (that is drained every day...).

I get 78% of your supposed "benefits"...for free...I really would encourage you to not worry about it...


This is correct.
 
I drill a hole in my rim opposite the valve and install another valve. This is a vent to purge with pure nitrogen for about 24 hours before filling to pressure.
 
Originally Posted By: SteveSRT8
I am amazed at N2's staying power. You'd think this was debunked years ago.


"Staying Power"?

Try those 200 mpg carbs from the 1950's. They still come up from time to time.
 
My elderly father still swears that he knew a guy in the (either 1950's or 1960's) who had an uncle who bought a new Ford that went for thousands of miles on a quarter of a tank of fuel. The story goes that Ford accidently released it, and then bought the car back from the owner after the mistake was discovered for several times it's original purchase price. Of course, my dad never saw the car in person or met the actual owner.

I just close my eyes and nod my head when he tells the story-I know there's no way I'll ever convince him it was just another urban legend.
 
Originally Posted By: Astro14
Leave the N2 to race cars and airplanes. Check your tires monthly and fill them with dry air.
Don't miss the fact that most tire shops that push N2 have nitrogen CONCENTRATORS. Branick used to have specifications on theirs, but seem to have removed them ... but my memory is that the output is in the 95% range as normally operated.

BUT ... they point out that O2 permeates back in to an equilibrium of 93.4%. See http://www.branick.com/Nitrogen - What you Need to Know/Optimal Purity Levels.pdf

The bottles have "pure nitrogen", typically well over 99% for "industrial" grade, and better for analytical.

As has been said here, it is the water vapor you want to be rid of ...
 
Originally Posted By: MobilinHyundia
We use nitrogen in aircraft tires for years now. So why not use them in car tires!
Costco use nitrogen in their tires with free top ups. Sound like a good deal for me.


If it were free, I would.

But I refuse to pay extra for the same level of performance...you did follow the discussion, right? And realize that there is no real performance benefit (save dryness) in a passenger car?
 
Originally Posted By: Astro14
And realize that there is no real performance benefit (save dryness) in a passenger car?


You are not really that uninformed. So I conclude that real means something to you other than what it means to me. You are not going to say that N2 does not leak out, so you must be saying that it is not a "real" advantage since you top up your tires every month. Do you really want to maintain that losing pressure slower is not a "real" advantage? Does that mean that you think that pressure going down slower over time is imaginary?

You are not going to deny the fact that a tire with N2 loses pressure more slowly than with air.
 
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If they use a Nitorgen concentrator rather than a cylinder, you've got 5% oxygen in there in the first place.

Are you saying that you'll happily spend $20 on something that's virtually immeasurable ?

Scientifically, You'll never get your $20 back.

And if you "beleive" that the tyres aren't going to lose pressure, you'll be less likely to check regularly, and more likely to end up in the condition that N2 is supposed to prevent...underinflated.
 
Nitrogen is great for most people.

And by most people...I mean the kinda people who never check oil/coolant/tire pressure/if their car has gas before a light comes on...
 
Originally Posted By: Carbon
Originally Posted By: Astro14
And realize that there is no real performance benefit (save dryness) in a passenger car?


You are not really that uninformed. So I conclude that real means something to you other than what it means to me. You are not going to say that N2 does not leak out, so you must be saying that it is not a "real" advantage since you top up your tires every month. Do you really want to maintain that losing pressure slower is not a "real" advantage? Does that mean that you think that pressure going down slower over time is imaginary?

You are not going to deny the fact that a tire with N2 loses pressure more slowly than with air.



Please re-read my other posts...I don't have time to re-type it all...You don't lose pressure that much slower...you still lose the same amount of pressure with drops in temperature...the touted benefits are so minor as to not be worth the expense...

I'm not uninformed, not an engineer either, I'm just a simple guy with a degree in Astrophysics who recognizes "hogwash" when I see it...
 
Originally Posted By: Astro14


Please re-read my other posts...I don't have time to re-type it all...You don't lose pressure that much slower...you still lose the same amount of pressure with drops in temperature...the touted benefits are so minor as to not be worth the expense...


"Not worth the expense" is way different from "no real advantage".

You know what your time is worth. You may even enjoy tending to your tires. Maybe if your degree was MD, you might find the expense worthwhile. You may find having your tires changed when the tread is down to 5/32 to be not worth the expense. Paying for N2 in the tires is not worth the expense to me, but there is a non-imaginary benefit to N2 in passenger car tires.

Regarding losing pressure during temperature drops, you get that pressure back when the temperature comes back up. So a tire filed with N2 in August will have more pressure on that cold January day than one filled with air. The extra mile or so between fuel fill-ups during December, for example, would be small, but it's real.
 
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Nitrogen is dry, compressed air is typically not.

Wet air inside a tire mounted on Aluminum rims will contribute to the formation of corrosion leading to rim leaks over time.

Reputable tire shops include free rim leak repairs in their services. If they can get the customer to pay extra money for dry 100% Nitrogen rather than wet 78% Nitrogen, it will be a cash bonanza for the Tire Shop.

They could also install air dryers on their compressors which would do the same thing, PLUS prolong the life of all their air tools, but customers wouldn't pay extra for that.
 
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Originally Posted By: Carbon
Originally Posted By: Astro14


Please re-read my other posts...I don't have time to re-type it all...You don't lose pressure that much slower...you still lose the same amount of pressure with drops in temperature...the touted benefits are so minor as to not be worth the expense...


"Not worth the expense" is way different from "no real advantage".

You know what your time is worth. You may even enjoy tending to your tires. Maybe if your degree was MD, you might find the expense worthwhile. You may find having your tires changed when the tread is down to 5/32 to be not worth the expense. Paying for N2 in the tires is not worth the expense to me, but there is a non-imaginary benefit to N2 in passenger car tires.

Regarding losing pressure during temperature drops, you get that pressure back when the temperature comes back up. So a tire filed with N2 in August will have more pressure on that cold January day than one filled with air. The extra mile or so between fuel fill-ups during December, for example, would be small, but it's real.


Air is 72% N2 (you did read the whole thread, right?) and the diffusion difference between O2 and N2 is slight. So, the 72% mix of N2 will diffuse only slightly faster through the rubber tire...it's measurable...but not really significant...

Face it, N2 diffuses through the tire as well, and you lose it over time.

In most North American climates, you're going to have average temperature swings of 50 - 60 degrees...application of PV=nRT (and N2 is a gas, subject to the same laws) tells you that an average tire will then be roughly 6 PSI low as a result of that change in temperature. The tire filled with air will lose about 1 PSI/month, so in January, you'll be about 11 PSI low. You have to fill them up.

The N2-filled tire will have lost about 0.9 PSI/month from August to January, leaving you roughly 10 PSI low. If you run your tires 10 PSI low, you're a moron.

Tires filled with air have to be filled to compensate for temperature changes, tires filled with air have to be filled to compensate for lost air.

Tires filled with N2 have to be filled to compensate for temperature changes, they have to be filled to replace lost N2.

So, where's the advantage?

Dryness...and I can do that with my compressor...so there is a measurable, but very small difference in loss rate...and I call that no real difference.

Look, I don't mind how you spend your money...but you should know what you're getting for it...in this case, not much.
 
Originally Posted By: tommygunn
Nitrogen is great for most people.

And by most people...I mean the kinda people who never check oil/coolant/tire pressure/if their car has gas before a light comes on...


How? You have to check them just as often, you have to fill them up just as often...N2 is not some maintenance-free wonder gas...please read through the whole thread...read the article that was linked.
 
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