Nitrogen in tires

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by henryroten, Aug 25, 2012.

  1. henryroten

    henryroten Been here awhile

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    I was thinking that with this hot summer and all the reports about tire failures I would try replacing the air in my tires with Nitrogen gas. I know that race car drivers everywhere use it as it doesn't expand with heat, keeping the tire pressure from over heating and inflating the tires to dangerous levels (Nitrogen gas is also used in shocks for the same reasons).

    So my first attempt (pulled the valve stem and tried to squeeze the air out) went fairly well but still I found that the tires would grow in pressure 3-4 pounds on hot highway speeds. So I then let them cool off and topped them off at 34 front and 40 rear (didn't start over, just added Nitrogen) and found that after 75 'spirited' miles on the twisties that the front stayed at 34 and the rear grew to 41.5 pounds. Not bad! the tires also felt (to the hand) to be cooler so I am so far pretty pleased with the swap.

    The other benefit is that pressure should stay equal in elevation changes which are plentiful in the area where I do most of my riding (northern Utah).

    Just thought I would share.
    #1
  2. biggus

    biggus Been here awhile

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    I read about filling your tires with nitrogen from the makers of Dynabeads. Glad that someone on here has actually done it.

    I have wanted to do this to mine since I live in Thailand where the temps tend to be pretty hot.
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  3. Unkgd

    Unkgd Been here awhile

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    Compressed air always contains moisture - which is the major contributer to rising tire pressure when the tire warms up.
    Bottled nitrogen contains significantly less moisture (on the order of ppm if I remember correctly) hence - less pressure rise when heated.

    It would be possible to use an eductor to remove the air from the tubes prior to refilling with nitrogen - which would save one step from what the OP did.

    I have a bottle of nitrogen sitting in the hanger - might have to finally get arround to doing this:D
    #3
  4. catalina38

    catalina38 Long timer

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    I prefer 78% nitrogen.
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  5. biggus

    biggus Been here awhile

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    :roflMust be a diver.
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  6. bhorocks

    bhorocks Been here awhile

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    good idea...
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  7. catalina38

    catalina38 Long timer

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    I'm trying to avoid oxygen toxicity:lol3
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  8. timekeeper

    timekeeper Adventurer

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    I used Nitrogen in the tires of my GTR for 2 years. The hassel was NOT worth the results.:deal
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  9. sstewart

    sstewart Long timer

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    Molecules are larger,less leakage.:freaky
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  10. syzygy9

    syzygy9 Been here awhile

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    Hate to be the bearer if bad news but N2 in conventional tyres is a complete waste of time (apart from the fact that good ol' air in almost 80% N2) - great way for tyre retailers to make some extra money though.

    If however, you live in a very humid climate, conventional unfiltered air may have a lot of water in it which when condensing, evaporating or freezing (whatever the case may be) will result in pressure changes (which is one of the reasons commercial jets have N2 in their tyres). You could also argue that "pure" nitrogen does not have very much oxygen or water in it and being relatively inert does not react with the tyres, although I haven't heard of too many tyre failures caused by the rubber tyre compounds reacting/oxidising with air. With regard to pressure changes - pure air (no water) and N2 probably are both as close to an 'ideal' gas as each other and hence have same P to T ratios.
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  11. Nut Clutch

    Nut Clutch was Steve Lavigne

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    Right on.

    When I raced karts, I carried a nitrogen bottle around because it was a readily available source of consistently low moisture inert air. The size of the nitrogen molecules was not a concern. The important thing was to see a low and consistent tire pressure change due to heat. Nitrogen provided that. Also, you can get it from Praxair for something like $20 + deposit for a reasonably sized cylinder at 2000 psi. Just add a regulator and you are off to the races. :clap

    The 2000 psi cylinders are much more convenient at a remote location than a compressor that requires power and is noisy or a 5 gallon 125 psi tank that runs out quickly.
    #11
  12. SE Steve

    SE Steve Super Noob

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    My experience with nitrogen is with commercial truck tires. From what I have been told is that nitrogen molecules are larger than oxygen molecules. So over time the nitrogen filed tires will lose less air pressure from leaking through the rubber layers . Nitrogen keeps the air pressure more stable day to day. Example I was using nitrogen in the steer tires of my truck 18 wheeler axle loaded at 1200lbs tire pressure at 120 psi cold. After 600 hundred miles pressure would be around 140psi. The next morning around 118. so it would lose a couple lbs per day. With straight O2 tires would lose 5 psi per day. My opinion is nitrogen is a little more stable than straight air in tires. In motorcycle tires I can't see it making a big enough difference to worry about. Truck tires usually come apart because they don't have enough air pressure. Could be they have a slow leak. When truck tires run low they over heat and explode. If your worried about tire failer stop and check your tire pressure if it's higher than you like take a break and let your tire cool down. Just my 2 cents
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  13. Peanuts

    Peanuts Long timer

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    I used Helium in my 990 Adv tyres. The whole bike now weighs less than my 250 EXCF.


    Honest ;)

    I also lube my chain with snake oil :D
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  14. Azmontana

    Azmontana Adventurer

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    What hassle? It's a piece of piss to fill your tyres with Nitrogen.
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  15. Nomadix

    Nomadix Adventurer

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    For best results, I'd suggest a mixture comprising roughly 78% nitrogen, 21% oxygen and 1% argon. Don't worry about trace amounts of other gasses.

    Also, for optimum performance and longevity, I recommend snake-oil in your engine .
    #15
  16. Barman

    Barman Way Offline

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    Neon gas with opaque sidewalls...Bling! :lol3
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  17. Jaimoto

    Jaimoto Spaniard in Chile

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    Catalina38 uses the same percentage :hmmmmmyou guys know something we don't know.

    I use beer's nitrogen and always carry a six pack just in case.
    #17
  18. syzygy9

    syzygy9 Been here awhile

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    Air = ~80% N2 and ~20% O2, N is 7 on the periodic table and O is 8, add some trace elements (H2O and Ar) and I think you will find the average molecule size is larger for 'air' - for whatever that is worth.

    Pure N2 and O2 are both as close as to each other and to an 'ideal' gas that their PV to T relationship is virtually the same.

    Pressure changes for N2 vs 'air' filled tyres are due to the water in the air evaporating (=gas), condensing (=water), freezing (=ice) - effectively taking some of the 'gas' out of the tyre.

    'Air' filled tyres don't leak any more (or less) than pure N2 filled tyre - unbelievable how there is so much mythology around N2 in tyres!
    #18
  19. timekeeper

    timekeeper Adventurer

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    Azmontana, Piss,no it isn't yellow or wet:roflIt is a hassle every time you need to fill or adjust to have a can of Nitrogen there for that purpose. They market it as if your tires will never change PSI as you drive or temp changes,truth be known it does change just not AS much as compressed air. For someone with little experience on the reality of actually having it in one of there own rides I suppose it seems like the best thing since sliced bread. In reality if your tracking or touring tires do need adjustment and Nitrogen is not as available as the alternative, or worth the "hassle".:rayof
    #19
  20. catalina38

    catalina38 Long timer

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    Google is my friend

    Dry air contains roughly (by volume) 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.039% carbon dioxide, and small amounts of other gases
    #20