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    • CommentAuthorLyKqiD
    • CommentTimeSep 24th 2009
     
    Posted By: wes m.all the turds you have dumped on it.

    Ha!

    licked seriously, you have already threatened leaving and never coming back. This isnt a break up, we neednt know what you will do. C'mon this is strike two for you, most simple minded people dont keep acting like a jackass.
    • CommentAuthortoroadie
    • CommentTimeSep 25th 2009 edited
     
    Interesting..

    I agree with all of the above, H2 and He are going to go through a tire PDQ so are just not used for that reason alone.

    Just think about your average low pressure helium balloon the day after it was filled.

    But as an academic exercise.. All ideal gases follow the relationship PV=nRT; where P is pressure in Pa, V is volume in m^3, n is number of moles, R is the universal gas constant (8.31 J /mol K), and T is temperature in Kelvin (Celsius + 273.15).

    We want to compare two tires both with same pressure, volume and temperature so we know they will both have the same number of moles of whatever gas we use.

    So without any math we can see the weights will be directly related to their molar mass / molecular weight.

    H2 is 2.02 g/mol, He is 4.0, H2O is 18, N2 is 28, O2 is 30, Ar is 39.98, CO2 is 44 g/mol.

    So relatively you would only need (2.02/28) ~ 7% of the mass of Hydrogen gas to fill a tire that would otherwise be filled with Nitrogen. But again, no one does this because it is likely way too cumbersome and would just deflate very very quickly.

    As for absolute weights, we need to actually pin down pressures volumes etc.

    P lets say is 100psi and convert via 6.894x10^3 (Pa/psi) but since it is a gauge pressure we have to add the pressure of the atmosphere, a nominal 101kPa. Overall (100psi)(6.894x10^3 Pa/psi)+(101000 Pa) = 7.904x10^5 Pa

    V I'm going to have to fudge a bit, I'll use a 700x23c tire aka 23-622 tire and use half the bead seat diameter and half the inner diameter as the radius from center of tube to center of torus, and radius of tube. So V = 2 pi^2 R r^2 = 2 pi^2 (622mm/2) (23mm/2)^2 (1 m^3/(1000^3 mm^3)) = 8.12x10^-4 m^3

    T lets assume 25 Celsius (77F) = 298.15K

    So n = PV/RT = ( 7.904 x 10^5 )(8.12x10^-4)/((8.31)(298.15)) ~ 0.26 moles.

    So H2 would weigh ~ 0.5g while Nitrogen would weigh ~ 7g, CO2 would weigh 11g.

    Since CO2 is used as a common gas for filling tires I guess convenience outweighs any weight savings. (slightly heavier tires but smaller "pump" that can be tucked away aerodynamically).

    Mind you the volume is approximate and is likely an underestimate, but since the temperature I chose was cool the differences should balance out. Of course with pressures more than 100psi you can adjust as required.

    The 5 to 10 grams savings mentioned by ragnar is reasonable and sounds like a measured result.
  1.  
    Posted By: LyKqiD
    Posted By: wes m.all the turds you have dumped on it.

    Ha!

    licked seriously, you have already threatened leaving and never coming back. This isnt a break up, we neednt know what you will do. C'mon this is strike two for you, most simple minded people dont keep acting like a jackass.
    i'll act how i want and I have never mentioned the idea of leaving. where ever did you get that idea?
  2.  
    Posted By: CANosprayPAINToooo0
    (....) 0oooo
    .\...(.(....)
    ..\..)..)../
    .......(../..........i can hold two pieces of doo-doo in my hand!.............this thread is.....what it is!


    Yay! De La Soul!
  3.  
    there is a device that lets riders instantly inflate their tubes with those bb gun co2 cartridges.
    • CommentAuthorthe rabbi
    • CommentTimeSep 25th 2009
     
    Posted By: lickedwickedthere is a device that lets riders instantly inflate their tubes with those bb gun co2 cartridges.
    this is old news.
    • CommentAuthorAaron C
    • CommentTimeSep 25th 2009
     
    i think more PS Lickedwicked images are in order. that seemed to work for a while.
    • CommentAuthorLyKqiD
    • CommentTimeSep 25th 2009 edited
     
    Most people I knew used those co2 inflators in order to crack nitrous chargers for doing whipits.



    Posted By: Aaron Ci think more PS Lickedwicked images are in order.

    We all know there is plenty of material to use of him on the interweb.
  4.  
    I think he just needs more guidance, and sadly we arent doing him any favors here. If hes as young as some say he is, I surely dont know how old he is, but if he is that young, he just needs to be taught some things, no offense licked, we all were young once and had to learn. And yes you do come up with some strange stupid more than common sense topics, im sure some of that has to do with being young, needing attention, or whatever. Anyways, I would just chalk all this silly nonsense, and bashing up as a learning experience and take it and use it for the good. If that makes any sense...
    • CommentAuthorsfbee
    • CommentTimeSep 25th 2009
     
    • CommentAuthorAaron C
    • CommentTimeSep 25th 2009 edited
     
    Posted By: sfbeeNSFW


    Oh no you di'dn't.
  5.  
    those aren't me but continue if you please. worst you could do is hurt my cousin who doesn't even come here.
    • CommentAuthorsfbee
    • CommentTimeSep 25th 2009 edited
     
    Posted By: Aaron COh no you di'dn't.


    YES, I DONE DID!

    +1 for productivity at work

  6.  
    Hahahahaha!!!

    Oh Velospace how I love thee
  7.  
    Posted By: sfbee


    Look at that asshole hahaaha
    • CommentAuthorAaron C
    • CommentTimeSep 26th 2009
     
    Posted By: lickedwickedthose aren't me but continue if you please. worst you could do is hurt my cousin who doesn't even come here.


    ahhhhhh! lickedwicked has a cousin named lickedwicked! wait, what? my mind is so fucked...
    • CommentAuthorfixedpuch
    • CommentTimeSep 26th 2009
     
    Where does the poo come out? his mouth?
    • CommentAuthorheadydude
    • CommentTimeSep 26th 2009
     
    wow. is it just me or is everyone just crying their little eyes out over this? seemed to me like licked has a legit question about what goes into your tires and how it affects your ride. give the guy a break. stop wasting time at work to bitch the guy out. remember: IT'S JUST THE INTERNET.
  8.  
    i wouldn't continue if i wasn't feeling like my questions were legit. sfbee, you forgot to spam my other posts. but thanks for doing it. i'll feel like a martyr one day. when generations after me look back, you'll be the villain.
    • CommentAuthorLyKqiD
    • CommentTimeSep 26th 2009
     
    headydude, you would be right if you werent talking about the same kid whom has posts 6 discussions in the last 3 days.
    The same kid who posts questions like:

    Just like cars are should bikes be hands free?

    how does music affect fashion and vice versa?

    celebrities and fixed, good or bad?

    when I see an unlocked bike that's not mine, should I deflate either or both tires to deter thieves?

    Are conversions safer than a track drop out? When the chain snaps, the axel can still be held in the frame. But in track drop outs the wheel can slip off.

    are the differences so big that it's a seperate catagory of bike? i don't see the need for a special type of bike when the bike used is only a small portion of the race.

    Has anybody ever found a good deal on ebay and won it? How good are deals on ebay?
 
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