Re: Helium Filled Tubes

Discussion in 'Cycling Equipment' started by [email protected], Jan 19, 2005.

  1. I have spent most of this night researching the benefits of using
    Nitrogen in passenger car tires. Today, I had the air "removed" from
    my new Jetta Wagon which has sport suspension and 17" wheels. I
    immediately noted the difference in a smoother ride. Most of the posts
    that I have read on the internet don't understand why there is any
    benefit to using Nitrogen. Some sites state that it has something to
    do with Boyle's Law. But, I found it has more to do with Dalton's Law
    which states: Each gas exerts its own pressure. In formula: pv = nRT.
    Because oxygen contracts and expands differently than Nitrogen and that
    oxygen molecules are smaller than Nitrogen, it makes sense that the
    pressure is more stable and less prone to leaks.

    My 2 cents,
    Kbatzler

    [email protected] wrote:
    > In germany cars use NO2 because it does not heat up like air and the

    tire
    > pressure remains consistnt. I am told it produces a better ride. All

    good
    > reasons when using a 17 MM bike tire on a track with 230 PSI in it.
    > Andrew Poodle wrote in message <[email protected]>...
    > >I believe (I may be wrong) that helium isn't used due to it's

    molecular
    > size being so
    > >small that your tyres would deflate quite quickly..
    > >
    > >Just my tuppence worth
    > >
    > >Andrew
    > >
    > >Adam Simpson wrote:
    > >
    > >> The reason Nitrogen is used in temperature-sensitive situations is

    that
    > >> nitrogen is quite insensitive to temperature changes and in the

    case of
    > >> racing tires, nitrogen will not burn in the presence of a spark.
    > >> For the first reason stated, nitrogen is the best substance for

    > suspension
    > >> damping because it is not sensitive to the temperature changes a
    > >> shock may experience.
    > >>
    > >> ILuvMyCheV ([email protected]) wrote:
    > >> : "J. Michaels" <[email protected]> wrote:
    > >>
    > >> : >20 years ago, some people used nitrogen in their car tires for

    rally
    > events.
    > >>
    > >> : Without commenting on why, I can tell you that they still use it

    in
    > road racing
    > >> : tires. I was at the 24 Hours of Daytona this year and there was

    an
    > area of the
    > >> : pits where dozens upon dozens of N2 bottles were stored.
    > >>
    > >> : Aric Pogel
    > >>
    > >> --
    > >> Adam Simpson (MTBfreak) / [email protected]
    > >> / [email protected]

    > >
    > >--
    > >While you're spamming me, don't forget to include these guys:
    > >Chairman Reed Hundt: [email protected] Comm. James Quello:

    [email protected]
    > >Comm. Susan Ness: [email protected] Comm. Rachelle Chong:

    [email protected]
    > >US Postal Service: [email protected] Fraud Watch:

    > [email protected]
    > >Federal Trade Commission: [email protected]
    > >
    > >Oh, and while you're at it, pound some sand too!
    > >[email protected] [email protected] [email protected]

    [email protected]
    > >[email protected]$HOST [email protected] [email protected]
    > >
    > >
     
    Tags:


  2. Leo Lichtman

    Leo Lichtman Guest

    <[email protected]> wrote: (clip) I immediately noted the difference in a
    smoother ride. (clip)
    ^^^^^^^^^^^^^^^
    I think in a true blindfold test. you would not be able to tell the
    difference. (semi-TIC)
     
  3. Tom Sherman

    Tom Sherman Guest

    Leo Lichtman wrote:

    > <[email protected]> wrote: (clip) I immediately noted the difference in a
    > smoother ride. (clip)
    > ^^^^^^^^^^^^^^^
    > I think in a true blindfold test. you would not be able to tell the
    > difference. (semi-TIC)


    Campy equipped bikes ride best with air bottled in Vicenza, while
    Shimano equipped bicycles should use air bottled at the summit of Mt. Fuji.

    --
    Tom Sherman - Near Rock Island
     
  4. On Wed, 19 Jan 2005 18:30:12 -0800, kbatzler wrote:

    > I have spent most of this night researching the benefits of using
    > Nitrogen in passenger car tires. Today, I had the air "removed" from
    > my new Jetta Wagon which has sport suspension and 17" wheels. I
    > immediately noted the difference in a smoother ride. Most of the posts
    > that I have read on the internet don't understand why there is any
    > benefit to using Nitrogen. Some sites state that it has something to
    > do with Boyle's Law. But, I found it has more to do with Dalton's Law
    > which states: Each gas exerts its own pressure. In formula: pv = nRT.
    > Because oxygen contracts and expands differently than Nitrogen and that
    > oxygen molecules are smaller than Nitrogen, it makes sense that the
    > pressure is more stable and less prone to leaks.


    Ummm. Horseshit. What do you think "air" is, anyway? 75% of air, or
    more, is precisely nitrogen. The rest is oxygen, carbon dioxide, and
    farts.

    --

    David L. Johnson

    __o | You will say Christ saith this and the apostles say this; but
    _`\(,_ | what canst thou say? -- George Fox.
    (_)/ (_) |
     
  5. Jim Adney

    Jim Adney Guest

    On 19 Jan 2005 18:30:12 -0800 [email protected] wrote:

    >I have spent most of this night researching the benefits of using
    >Nitrogen in passenger car tires. Today, I had the air "removed" from
    >my new Jetta Wagon which has sport suspension and 17" wheels. I
    >immediately noted the difference in a smoother ride. Most of the posts
    >that I have read on the internet don't understand why there is any
    >benefit to using Nitrogen. Some sites state that it has something to
    >do with Boyle's Law. But, I found it has more to do with Dalton's Law
    >which states: Each gas exerts its own pressure. In formula: pv = nRT.
    >Because oxygen contracts and expands differently than Nitrogen and that
    >oxygen molecules are smaller than Nitrogen, it makes sense that the
    >pressure is more stable and less prone to leaks.


    Is this a troll, or have you just never had a physics course?

    -
    -----------------------------------------------
    Jim Adney [email protected]
    Madison, WI 53711 USA
    -----------------------------------------------
     
  6. On 19 Jan 2005 18:30:12 -0800, [email protected] wrote:

    >I have spent most of this night researching the benefits of using
    >Nitrogen in passenger car tires. Today, I had the air "removed" from
    >my new Jetta Wagon which has sport suspension and 17" wheels. I
    >immediately noted the difference in a smoother ride. Most of the posts
    >that I have read on the internet don't understand why there is any
    >benefit to using Nitrogen. Some sites state that it has something to
    >do with Boyle's Law. But, I found it has more to do with Dalton's Law
    >which states: Each gas exerts its own pressure. In formula: pv = nRT.
    >Because oxygen contracts and expands differently than Nitrogen and that
    >oxygen molecules are smaller than Nitrogen, it makes sense that the
    >pressure is more stable and less prone to leaks.
    >
    >My 2 cents,
    >Kbatzler
    >
    >[email protected] wrote:
    >> In germany cars use NO2 because it does not heat up like air and the

    >tire
    >> pressure remains consistnt. I am told it produces a better ride. All

    >good
    >> reasons when using a 17 MM bike tire on a track with 230 PSI in it.
    >> Andrew Poodle wrote in message <[email protected]>...
    >> >I believe (I may be wrong) that helium isn't used due to it's

    >molecular
    >> size being so
    >> >small that your tyres would deflate quite quickly..
    >> >
    >> >Just my tuppence worth
    >> >
    >> >Andrew
    >> >
    >> >Adam Simpson wrote:
    >> >
    >> >> The reason Nitrogen is used in temperature-sensitive situations is

    >that
    >> >> nitrogen is quite insensitive to temperature changes and in the

    >case of
    >> >> racing tires, nitrogen will not burn in the presence of a spark.
    >> >> For the first reason stated, nitrogen is the best substance for

    >> suspension
    >> >> damping because it is not sensitive to the temperature changes a
    >> >> shock may experience.
    >> >>
    >> >> ILuvMyCheV ([email protected]) wrote:
    >> >> : "J. Michaels" <[email protected]> wrote:
    >> >>
    >> >> : >20 years ago, some people used nitrogen in their car tires for

    >rally
    >> events.
    >> >>
    >> >> : Without commenting on why, I can tell you that they still use it

    >in
    >> road racing
    >> >> : tires. I was at the 24 Hours of Daytona this year and there was

    >an
    >> area of the
    >> >> : pits where dozens upon dozens of N2 bottles were stored.
    >> >>
    >> >> : Aric Pogel
    >> >>
    >> >> --
    >> >> Adam Simpson (MTBfreak) / [email protected]
    >> >> / [email protected]
    >> >
    >> >--
    >> >While you're spamming me, don't forget to include these guys:
    >> >Chairman Reed Hundt: [email protected] Comm. James Quello:

    >[email protected]
    >> >Comm. Susan Ness: [email protected] Comm. Rachelle Chong:

    >[email protected]
    >> >US Postal Service: [email protected] Fraud Watch:

    >> [email protected]
    >> >Federal Trade Commission: [email protected]
    >> >
    >> >Oh, and while you're at it, pound some sand too!
    >> >[email protected] [email protected] [email protected]

    >[email protected]
    >> >[email protected]$HOST [email protected] [email protected]
    >> >
    >> >


    Dear K.,

    You'd think that it has something to do with the size of the
    molecules, but it doesn't.

    The reason that pure N2 (78% in air) is preferred in tires
    is that it isn't as soluble in rubber as the O2 (21% in air)
    and much less soluble than CO2 (0.3% in air, but 100% in
    quick-inflate cartridges).

    You can see details and a link to why rubber balloons don't
    hold air here:

    http://groups.google.co.uk/[email protected]&rnum=1

    Helium party balloons, for example, have that familiar shiny
    metal film because the gas hardly dissolves into metal at
    all, but drools through rubber quite rapidly. The metal film
    balloons are ugly, but they hold helium much longer than the
    more attractive soft balloons.

    Carl Fogel
     
  7. Werehatrack

    Werehatrack Guest

    On 19 Jan 2005 18:30:12 -0800, [email protected] may have said:

    >I have spent most of this night researching the benefits of using
    >Nitrogen in passenger car tires. Today, I had the air "removed" from
    >my new Jetta Wagon which has sport suspension and 17" wheels. I
    >immediately noted the difference in a smoother ride.


    It is impossible for any gas to behave in a manner that is different
    in any significant respect from any other gas at the same pressure in
    a tire. If you noticed a difference, then the pressures were not the
    same.

    >Most of the posts
    >that I have read on the internet don't understand why there is any
    >benefit to using Nitrogen.


    That's because there isn't one in most cases.

    Using a non-oxidizing fill gas in a tire is of benefit only when the
    following conditions may obtain:

    -- The tire has a heavy casing that may be able to heat up on the
    interior surface to the point where the tire material begins to evolve
    a combustible gas without losing sufficient structural integrity to
    fail. (Automotive tires will generally fail well short of this
    point.)

    -- The tires are operated at a high enough pressure that the
    accumulation of combustible gases as a result of extreme heating will
    produce a mixture with sufficient energy production capability on
    ignition to explode with force enough to shatter the tire.
    (Automotive tires seldom operate at these pressures; it would be
    difficult to achieve these conditions with only 35psi of normal air in
    the tire.)

    -- Some portion of the inflation cavity reaches ignition
    temperature for the resulting mixture. (Once again, automotive tires
    will fail before this point is reached.)

    So, where is a nitrogen fill worthwhile? In large truck tires, some
    construction equipment, some industrial equipment in
    continuously-operated machinery, and large aviation tires.

    In particular, on heavy trucks using dual wheels, the use of a
    non-oxidizing fill gas will ensure that the failure mode for an
    underinflated tire is nonexplosive. It should be noted that if the
    conditions which could generate such an exlosion are in fact achieved,
    the tire will fail due to the damage caused from the heating in any
    event; this merely removes the additional hazard posed by the
    explosion.

    There is no benefit in using a nitrogen fill on any normal-profile
    automotive tire, it is questionable if there is any benefit in using a
    nitrogen fill in an ultra-low-profile tire since the pressure is not
    high enough to support generation of an explosive force great enough
    to damage the tire even if the highly unlikely set of conditions could
    be achieved to cause that explosion, and the benefit in light truck
    tires is probably minimal.

    >Some sites state that it has something to
    >do with Boyle's Law. But, I found it has more to do with Dalton's Law
    >which states: Each gas exerts its own pressure. In formula: pv = nRT.
    >Because oxygen contracts and expands differently than Nitrogen


    This is an overstatement. The difference involved is so miniscule
    that there is nothing to be gained which the vehicle operator could
    possibly perceive. The condensation temperatures of the majority of
    atmospheric gases are so far below STP that their behavior at normal
    operating temperatures is essentially identical. Do the math and you
    will confirm this.

    >and that
    >oxygen molecules are smaller than Nitrogen, it makes sense that the
    >pressure is more stable and less prone to leaks.


    With few exceptions, molecular size has less of a bearing on gas loss
    through a tire's casing than the solubility of the gas in the tire's
    interior compounds. Tire interiors are formulated using polymers that
    are selected for their resistance to atmospheric gas, so the subject
    of what makes a good fill gas is rather moot; unless you were to
    employ helium (which does, in fact, escape through the tire's casing
    too readily), the rate of gas loss is quite small.

    The common belief that air in tires escapes through the pores of the
    rubber dates back to the days when tires were made of that material.
    Today's automotive tires are not made of rubber; they are made from
    complex polymer mixtures derived from petrochemical sources, and they
    do not have the same properties as rubber in most areas. Yes, there is
    still some gradual loss of air from automotive tires even with the
    modern materials, but differential gas loss rates do not favor
    nitrogen to any significant extent. The current fad for its use in
    automotive tire inflation is just that; a fad. It is a valid
    technique for preventing certain events in tires of higher pressure
    ond stiffer construction if they are at risk of severe interior heat
    buildup, but its value in automotive tires is entirely as a marketing
    gimmick.

    --
    My email address is antispammed; pull WEEDS if replying via e-mail.
    Typoes are not a bug, they're a feature.
    Words processed in a facility that contains nuts.
     
  8. Werehatrack

    Werehatrack Guest

    On Wed, 19 Jan 2005 21:06:53 -0600, Tom Sherman
    <[email protected]> may have said:

    >Leo Lichtman wrote:
    >
    >> <[email protected]> wrote: (clip) I immediately noted the difference in a
    >> smoother ride. (clip)
    >> ^^^^^^^^^^^^^^^
    >> I think in a true blindfold test. you would not be able to tell the
    >> difference. (semi-TIC)

    >
    >Campy equipped bikes ride best with air bottled in Vicenza, while
    >Shimano equipped bicycles should use air bottled at the summit of Mt. Fuji.


    But in the case of air from Fuji, the air must be from the cycling
    season. French bikes, of course, should only have their tires
    inflated with Perri-air.

    --
    My email address is antispammed; pull WEEDS if replying via e-mail.
    Typoes are not a bug, they're a feature.
    Words processed in a facility that contains nuts.
     
  9. [email protected] wrote:
    > I have spent most of this night researching the benefits of using
    > Nitrogen in passenger car tires.


    You need to do more research.

    a.) N2 is great in car tires used in performance applications for two
    reasons:

    1 - It's cheap as a compressed gas.

    2 - Unlike compressed atmospheric air, it contains very little water
    vapor.

    b.) N2 is great in bike tires if you already have a source for your
    auto tires because you don't have to physically manipulate a floor
    pump.

    c.) N2 exhibits non-ideal behavior WRT temperature changes. But the
    range of temperature changes (in Kelvin) that an auto tire might
    undergo is so small as to be insignificant, when compared to volume and
    pressure.

    But if you want your car (or bike) to be lighter, use He.
    :)

    HAND,

    E.P.
     
  10. John Dacey

    John Dacey Guest

    On Wed, 19 Jan 2005 23:20:32 -0700, [email protected] wrote:


    >You'd think that it has something to do with the size of the
    >molecules, but it doesn't.
    >
    >The reason that pure N2 (78% in air) is preferred in tires
    >is that it isn't as soluble in rubber as the O2 (21% in air)
    >and much less soluble than CO2 (0.3% in air, but 100% in
    >quick-inflate cartridges).


    Are there any gasses whose thermal expansion rates would make them
    less likely than air to cause bicycle tire blowoffs on steep descents?
    -------------------------------
    John Dacey
    Business Cycles, Miami, Florida
    Since 1983
    Comprehensive catalogue of track equipment: online since 1996.
    http://www.businesscycles.com
     
  11. On Thu, 20 Jan 2005 13:58:53 -0500, John Dacey
    <[email protected]> wrote:

    >On Wed, 19 Jan 2005 23:20:32 -0700, [email protected] wrote:
    >
    >
    >>You'd think that it has something to do with the size of the
    >>molecules, but it doesn't.
    >>
    >>The reason that pure N2 (78% in air) is preferred in tires
    >>is that it isn't as soluble in rubber as the O2 (21% in air)
    >>and much less soluble than CO2 (0.3% in air, but 100% in
    >>quick-inflate cartridges).

    >
    >Are there any gasses whose thermal expansion rates would make them
    >less likely than air to cause bicycle tire blowoffs on steep descents?
    >-------------------------------
    >John Dacey
    >Business Cycles, Miami, Florida
    >Since 1983
    >Comprehensive catalogue of track equipment: online since 1996.
    >http://www.businesscycles.com


    Dear John,

    Nope.

    Werehatrack explained this to kblatzler:

    [kblatzler believed hopefully:]
    >>Some sites state that it has something to
    >>do with Boyle's Law. But, I found it has more to do with Dalton's Law
    >>which states: Each gas exerts its own pressure. In formula: pv = nRT.
    >>Because oxygen contracts and expands differently than Nitrogen


    [werehatrack disillusioned him:]
    >This is an overstatement. The difference involved is so miniscule
    >that there is nothing to be gained which the vehicle operator could
    >possibly perceive. The condensation temperatures of the majority of
    >atmospheric gases are so far below STP that their behavior at normal
    >operating temperatures is essentially identical. Do the math and you
    >will confirm this.


    At ordinary temperatures and modest pressures (the STP, or
    standard temperature and pressure above), gas is pretty much
    gas when it comes to how much it expands when heated.
    Bicycle tires aren't cold enough or at a high enough
    pressure to condense the gases into liquid form.

    A 100 psi tire full of CO2 at 72F will reach the same
    pressure as a tire full of plain air or pure N2 or helium
    if the rim heats the gas to 200F.

    The difference in heating rates of the gases due to
    different masses would be negligible--compressed to 7
    atmospheres, about 100 psi, the mass in the tire is only
    about the mass of the air inside a modest shipping box.

    In this case, pigs is pigs.

    Carl Fogel
     
  12. Leo Lichtman

    Leo Lichtman Guest

    "John Dacey" wrote: Are there any gasses whose thermal expansion rates
    would make them less likely than air to cause bicycle tire blowoffs on steep
    descents?
    ^^^^^^^^^^^^^
    Any gas that you are likely to put in your tire is close to "ideal." This
    means that they all behave pretty much according to the perfect gas law, and
    exhibit the SAME coefficient of thermal expansion. So the answer is "no."
    If there is going to be a difference, it will be due to the thermal
    diffusivity of the gas, which will affect the rate at which the heat
    transfers from the rim. However, this will also affect the rate at which
    the gas loses heat to the surroundings, so the solution of the problem will
    be very complex. (And probably pointless.)
     
  13. John Dacey

    John Dacey Guest

    On Thu, 20 Jan 2005 19:24:58 GMT, "Leo Lichtman"
    <[email protected]> wrote:

    >
    >"John Dacey" wrote: Are there any gasses whose thermal expansion rates
    >would make them less likely than air to cause bicycle tire blowoffs on steep
    >descents?
    >^^^^^^^^^^^^^
    >Any gas that you are likely to put in your tire is close to "ideal." This
    >means that they all behave pretty much according to the perfect gas law, and
    >exhibit the SAME coefficient of thermal expansion. So the answer is "no."
    >If there is going to be a difference, it will be due to the thermal
    >diffusivity of the gas, which will affect the rate at which the heat
    >transfers from the rim. However, this will also affect the rate at which
    >the gas loses heat to the surroundings, so the solution of the problem will
    >be very complex. (And probably pointless.)


    Thank you.

    -------------------------------
    John Dacey
    Business Cycles, Miami, Florida
    Since 1983
    Comprehensive catalogue of track equipment: online since 1996.
    http://www.businesscycles.com
     
  14. John Dacey

    John Dacey Guest

    On Thu, 20 Jan 2005 12:21:54 -0700, Galahad Threepwood wrote:

    >On Thu, 20 Jan 2005 13:58:53 -0500, John Dacey
    ><[email protected]> wrote:


    >>Are there any gasses whose thermal expansion rates would make them
    >>less likely than air to cause bicycle tire blowoffs on steep descents?


    >At ordinary temperatures and modest pressures (the STP, or
    >standard temperature and pressure above), gas is pretty much
    >gas when it comes to how much it expands when heated.
    >Bicycle tires aren't cold enough or at a high enough
    >pressure to condense the gases into liquid form.


    With qualifiers like "ordinary" and "modest" it has been hard to get a
    handle on this. After all, we've seen that rim braking can generate
    sufficient heat to re-liquify tubular adhesives, melt tubes and raise
    pressure to the point of tire blowoff. Are those temps still ordinary
    and modest? Thanks to you and Leo L for clarifying the matter.

    >A 100 psi tire full of CO2 at 72F will reach the same
    >pressure as a tire full of plain air or pure N2 or helium
    >if the rim heats the gas to 200F.
    >
    >The difference in heating rates of the gases due to
    >different masses would be negligible--compressed to 7
    >atmospheres, about 100 psi, the mass in the tire is only
    >about the mass of the air inside a modest shipping box.
    >
    >In this case, pigs is pigs.


    Don't ever let Lord Elmsworth hear you say that.

    John Dacey
    Blandings Castle

    -------------------------------
    John Dacey
    Business Cycles, Miami, Florida
    Since 1983
    Comprehensive catalogue of track equipment: online since 1996.
    http://www.businesscycles.com
     
  15. meb

    meb New Member

    Joined:
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    At 60 psi, your mountain bike tire is reduced by 18g/tire (that's over half an ounce), at 45 psi you save 14g/tire. You could save another gram with Hydrogen beyond He.

    Along the lines gcsmchemist has alluded to- it is common to use nitrogen in race car tires, but that is to minimize moisture found in air. The water vapor causes pressure fluctuations as it vaporizes and condenses altering handling. Since bike tires aren't heating up as much with the sliding in turns, you don't have the same moisture issues. You could still save almost a gram/tire with the nitrogen instead of air.
     
  16. On Thu, 20 Jan 2005 15:13:07 -0500, John Dacey
    <[email protected]> wrote:

    >On Thu, 20 Jan 2005 12:21:54 -0700, Galahad Threepwood wrote:
    >
    >>On Thu, 20 Jan 2005 13:58:53 -0500, John Dacey
    >><[email protected]> wrote:

    >
    >>>Are there any gasses whose thermal expansion rates would make them
    >>>less likely than air to cause bicycle tire blowoffs on steep descents?

    >
    >>At ordinary temperatures and modest pressures (the STP, or
    >>standard temperature and pressure above), gas is pretty much
    >>gas when it comes to how much it expands when heated.
    >>Bicycle tires aren't cold enough or at a high enough
    >>pressure to condense the gases into liquid form.

    >
    >With qualifiers like "ordinary" and "modest" it has been hard to get a
    >handle on this. After all, we've seen that rim braking can generate
    >sufficient heat to re-liquify tubular adhesives, melt tubes and raise
    >pressure to the point of tire blowoff. Are those temps still ordinary
    >and modest? Thanks to you and Leo L for clarifying the matter.
    >
    >>A 100 psi tire full of CO2 at 72F will reach the same
    >>pressure as a tire full of plain air or pure N2 or helium
    >>if the rim heats the gas to 200F.
    >>
    >>The difference in heating rates of the gases due to
    >>different masses would be negligible--compressed to 7
    >>atmospheres, about 100 psi, the mass in the tire is only
    >>about the mass of the air inside a modest shipping box.
    >>
    >>In this case, pigs is pigs.

    >
    >Don't ever let Lord Elmsworth hear you say that.
    >
    >John Dacey
    >Blandings Castle
    >
    >-------------------------------
    >John Dacey
    >Business Cycles, Miami, Florida
    >Since 1983
    >Comprehensive catalogue of track equipment: online since 1996.
    >http://www.businesscycles.com


    Dear John,

    It is extremely unlikely that any any bicycle tire would
    generate (much less survive) temperatures or pressures
    sufficient to alter the behavior of one gas versus another.

    Here's a page with a table of the Centigrade temperatures
    and pressures in multiples of atmospheres at which some
    common gases liquify:

    http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch14/property.html

    The boiling points in Centigrade are for 1 atmosphere of
    pressure.

    CO2, for example will liquify at a sweltering 31C, about
    87F--if you also compress it to about 73 atmospheres, a
    little over a thousand psi.

    At normal air pressure, CO2 begins to boil at about -78C,
    about -108F, so frozen CO2 (dry ice) just turns directly
    from solid to gas at normal temperatures, skipping the
    liquid state and sublimating.

    B. Wooster
     
  17. A Muzi

    A Muzi Guest

    >>[email protected] wrote:
    >>>I have spent most of this night researching the benefits of using
    >>>Nitrogen in passenger car tires.


    > [email protected] Wrote:
    >>But if you want your car (or bike) to be lighter, use He.



    meb wrote:
    > At 60 psi, your mountain bike tire is reduced by 18g/tire (that's over
    > half an ounce), at 45 psi you save 14g/tire. You could save another
    > gram with Hydrogen beyond He.
    >
    > Along the lines gcsmchemist has alluded to- it is common to use
    > nitrogen in race car tires, but that is to minimize moisture found in
    > air. The water vapor causes pressure fluctuations as it vaporizes and
    > condenses altering handling. Since bike tires aren't heating up as much
    > with the sliding in turns, you don't have the same moisture issues. You
    > could still save almost a gram/tire with the nitrogen instead of air.


    I half-followed this "nitrogen" thread. I think I might
    have stumbled on its inception- Wall Street Journal's car
    column had a question about it - answer noted that Costco
    fills tires with nitrogen. Probably costs them little,
    gives an opportunity to look 'tech' and so distinguish their
    service dep't.


    --
    Andrew Muzi
    www.yellowjersey.org
    Open every day since 1 April, 1971
     
  18. John Dacey

    John Dacey Guest

    On Thu, 20 Jan 2005 17:07:34 -0700, [email protected] wrote:

    >It is extremely unlikely that any any bicycle tire would
    >generate (much less survive) temperatures or pressures
    >sufficient to alter the behavior of one gas versus another.


    >CO2, for example will liquify at a sweltering 31C, about
    >87F--if you also compress it to about 73 atmospheres, a
    >little over a thousand psi.


    I do a lot of work with track racers here. Some of them are already
    using tire inflation that's flirting with 20% of that number. If only
    those guys at Silca would put some real moxie in their floor pumps...

    >At normal air pressure, CO2 begins to boil at about -78C,
    >about -108F, so frozen CO2 (dry ice) just turns directly
    >from solid to gas at normal temperatures, skipping the
    >liquid state and sublimating.


    It sounds like the stages through which many rbt threads go: direct to
    gas without intermediate transitions.

    -------------------------------
    John Dacey
    Business Cycles, Miami, Florida
    http://www.businesscycles.com
    Since 1983
    Our catalog of track equipment: online since 1996
    -------------------------------
     
  19. Leo Lichtman

    Leo Lichtman Guest

    "A Muzi" wrote: (clip) Costco fills tires with nitrogen. Probably costs
    them little, gives an opportunity to look 'tech' and so distinguish their
    service dep't.
    ^^^^^^^^^^^^^
    Mental image of hammer hitting nail on head. :)
     
  20. Werehatrack

    Werehatrack Guest

    On Fri, 21 Jan 2005 01:42:32 -0600, A Muzi <[email protected]> may
    have said:

    >I half-followed this "nitrogen" thread. I think I might
    >have stumbled on its inception- Wall Street Journal's car
    >column had a question about it - answer noted that Costco
    >fills tires with nitrogen. Probably costs them little,
    >gives an opportunity to look 'tech' and so distinguish their
    >service dep't.


    Bingo. Marketing.

    --
    My email address is antispammed; pull WEEDS if replying via e-mail.
    Typoes are not a bug, they're a feature.
    Words processed in a facility that contains nuts.
     
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