Nitrogen and Air tires on same car.

Discussion in 'Gen 3 Prius Fuel Economy' started by Reaper, Apr 24, 2015.

  1. wjtracy

    wjtracy Senior Member

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    They say argon gas has been used luxury car tires years ago, they say it is quieter! OK Tesla lets have some argon!

    Here is a little more on the subject: The leak rate through the rubber will be related to the molecule size, what they call the Kinetic Diameter. So here are some numbers on the Internet:

    Kinetic Diameter, Angstroms
    Helium 2.58
    Water 2.65
    Hydrogen 2.97
    Argon 3.40
    Oxygen 3.54
    Nitrogen 3.75
    Methane 3.80
    CO2 3.90

    Keep in mind, small changes in molecular size mean big differences in leak rate through the tire. For example, O2 permeates about 3-4 times faster than N2. So water is a really small molecule (see above) so it permeates really fast. Argon looks impractical because it leaks faster than O2, whereas O2 is a pretty bad leaker. Its a good thing air is 79% N2! The only practical thing leaking slower than N2 would appear to be CO2. So if argon makes a tire quieter, would not CO2 also do so? And it would hold pressure better.
     
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  2. Former Member 68813

    Former Member 68813 Senior Member

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    wow, i learned something new, hydrogen is larger than water. [sorry, didn't mean to sound sarcastic]
     
    #42 Former Member 68813, Apr 26, 2015
    Last edited: Apr 26, 2015
  3. wjtracy

    wjtracy Senior Member

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    Note that above we are talking "Kinetic Diameter" which is what governs membrane leakage. Actual physical size is a differernt number I believe He is less than 1 Angstrom real size. Hmm that seems too big hope I got my units right. But the relative sizes above should be OK, but there is variation in numbers reported...the Kinetic Diameter is hard to measure.
     
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  4. Easy Rider 2

    Easy Rider 2 Senior Member

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    Sure, easy test.:)
    Problem IS that tires are not the same as plastic water bottles and the permeation rate depends mostly on the membrane involved.
    If your bottle was glass, you would have to wait centuries.
     
  5. Former Member 68813

    Former Member 68813 Senior Member

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    CR is very weak in the science department. IMHO, the main benefit is less oxidative tire damage. When NHTSA did a study on tire aging, they pumped them with 100% O2 and put in warmers. this way they accelerated tire aging to mere weeks instead of years.
     
  6. wjtracy

    wjtracy Senior Member

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    I don't use N2 but if it were cheap and easy to get, I'd use it for the modest benefits. I like that Costco uses it but I don't use Costco.
     
  7. bwilson4web

    bwilson4web i3 and Prime

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    AMEN!
    This has got me thinking about doing the experiment. CO{2} is fairly easy to obtain.

    Bob Wilson
     
  8. CR94

    CR94 Senior Member

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    That misses the point. Of course different materials have different permeabilities, but the kinetic diameter of gas molecules (see above) doesn't depend on the membrane material.
     
  9. CR94

    CR94 Senior Member

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    How can there be significant oxidative tire damage if most of the oxygen escapes, according to nitrogen advocates?
     
    #49 CR94, Apr 26, 2015
    Last edited: Apr 26, 2015
  10. fuzzy1

    fuzzy1 Senior Member

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    For some of us, it was very easy. Just stash a few left-over bottles from events in the car, and in the pantry. Forget them for a few years. Then rediscover them, and wonder why the still sealed bottles appear to have shrunk and crinkled a bit, as if some water was missing.
     
  11. wjtracy

    wjtracy Senior Member

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    Use of CO2 inflation is common for bike tires. Several people say it leaks about same as air or a little faster. So we'd have to study CO2 to see why it is not used more for car tires. I had no interest until I read that Argon made tires quieter...I am wondering about CO2. Of course, I don't know how much weight to put on argon/quietness comments.
     
  12. alekska

    alekska Active Member

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    CO2 will make tire to overheat....it's a known greenhouse gas ! :)
    On the other side, CO2 will freeze and tire will collapse at about -70 C
    I would not risk it

    Alex
     
  13. Easy Rider 2

    Easy Rider 2 Senior Member

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    Possible. Also possible that repeated heating and cooling forced some of the AIR out through leaks or permeation.
    The key could be whether or not the air space at the top looked like more or less air was in there.
     
  14. Easy Rider 2

    Easy Rider 2 Senior Member

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    :ROFLMAO:
    That was meant as a joke, right ?
     
  15. fuzzy1

    fuzzy1 Senior Member

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    The air space looks similar to new bottles. Though it is possible the filling machine settings have changed over the years, leaving less air today than in the old days.

    I should also note that when I was in the electronics industry, silicon die that required hermetic sealing for moisture protection were always encased in metal or ceramic packaging. The far more common plastic IC cases were never considered to be hermetic, so the die surfaces themselves required moisture defenses.
     
  16. lar.smith42

    lar.smith42 Active Member

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    As interesting as this conversation is I have to add my 2 cents. I have owned and driven several cars during the last 57 years I have been driving. I have never had a tire fail due to moisture inside it. The rubber will fail first. thats why you never keep a tire for more than 7 or 8 years no matter how much tread is left. Side wall gets weak from flexing, tire gets small cracks from weather changes and just age. (just like us old guys) . Nitrogen in your tires is a gimmick to make money by making you believe you really have to have it.
     
  17. Reaper

    Reaper Junior Member

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    I don't think people are selling nitrogen as a gimmick to make you think that you must have it.


    Nitrogen and regular air is like brighthouse vs Verizon. Some people like brighthouse and some people like Verizon. Some will talk bad about the other and give their testimony on why and some will talk about their experience on why it's good.
     
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  18. ETC(SS)

    ETC(SS) The OTHER One Percenter.....

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    I think that bottled water is a better analogy.
     
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  19. CR94

    CR94 Senior Member

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    In an old bottle that has not leaked, there's a little more gas (not exactly air) at the top, but considerably less liquid water. Therefore, the bottle collapses.
     
  20. wjtracy

    wjtracy Senior Member

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    whenever we get a thread like this going, I head out to the garage to fill my tires. and then I am covered
     
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