08redgt500 Posted August 5, 2008 Report Share Posted August 5, 2008 I had my tires filled with nitrogen and the tire pressure still changes as though it were just air?! The pressure shouldn't change, should it? Link to comment Share on other sites More sharing options...
KCMO-GT500 Posted August 5, 2008 Report Share Posted August 5, 2008 I had my tires filled with nitrogen and the tire pressure still changes as though it were just air?! The pressure shouldn't change, should it? since air is 79% nitrogen, why would you suspect different? Link to comment Share on other sites More sharing options...
08redgt500 Posted August 5, 2008 Author Report Share Posted August 5, 2008 since air is 79% nitrogen, why would you suspect different? Owned a MB once, replaced with GT500. Being an inert gas, nitrogen supposedly does not change density with changes in tire temp. In the MB with a TPMS(digital real-time pressure readout) it stayed within 1-2lbs. of cold tire temp, at all times. In another car I drive daily, also with digital TPMS readout for each tire the pressures change by at least 5 pounds cold vs. hot. Just wondering if the second car dealer is not really filling the tires with nitrogen, but charging for it anyway? Link to comment Share on other sites More sharing options...
ingram4868 Posted August 5, 2008 Report Share Posted August 5, 2008 you've got this car pampering real bad :bandance: so where do I find this stuff and is it expensive? Link to comment Share on other sites More sharing options...
ilmor Posted August 5, 2008 Report Share Posted August 5, 2008 I also thought if you used 100% nitrogen, the pressures would not change, or very little. Link to comment Share on other sites More sharing options...
formervettowner Posted August 5, 2008 Report Share Posted August 5, 2008 you've got this car pampering real bad :bandance: so where do I find this stuff and is it expensive? Costco and its free. Link to comment Share on other sites More sharing options...
BoneDoc Posted August 5, 2008 Report Share Posted August 5, 2008 Owned a MB once, replaced with GT500. Being an inert gas, nitrogen supposedly does not change density with changes in tire temp. In the MB with a TPMS(digital real-time pressure readout) it stayed within 1-2lbs. of cold tire temp, at all times. In another car I drive daily, also with digital TPMS readout for each tire the pressures change by at least 5 pounds cold vs. hot. Just wondering if the second car dealer is not really filling the tires with nitrogen, but charging for it anyway? all gasses change density when temperature changes. this is described by the "ideal gas law" ... an equation that defines the relationship between Temperature, pressure and volume of a gas. here is linky: http://hyperphysics.phy-astr.gsu.edu/hbase...tic/idegas.html "Professor Bonedoc" out! Link to comment Share on other sites More sharing options...
Boss Doctor Posted August 5, 2008 Report Share Posted August 5, 2008 all gasses change density when temperature changes. this is described by the "ideal gas law" ... an equation that defines the relationship between Temperature, pressure and volume of a gas. here is linky: http://hyperphysics.phy-astr.gsu.edu/hbase...tic/idegas.html "Professor Bonedoc" out! +1 on what Professor BoneDoc said. A Nobel Gas is inert under normal circumstances because its outer valence shell, (layer of electrons), is full already, but they will expand/contract according to temperature. Link to comment Share on other sites More sharing options...
northportboss Posted August 5, 2008 Report Share Posted August 5, 2008 We have had it in our daily drivers here in Florida for over 7 months and love it. Not one problem with loosing air with the changing temperatures here in Florida. Link to comment Share on other sites More sharing options...
03 DSG Snake Posted August 5, 2008 Report Share Posted August 5, 2008 Wouldn't you need to get all the air out of the tire before refilling with nitrogen? Maybe it wasn't drained completely? I've never tried it, but the idea is intriguing. Link to comment Share on other sites More sharing options...
DubbsFaris Posted August 5, 2008 Report Share Posted August 5, 2008 My dealer did it to mine...just ask...they didn't charge me either... Haven't had a tire pressure problem...but unlike you guys in the north, I garage mine for these hot summer months...a black vert with leather seats = hot as hades... Link to comment Share on other sites More sharing options...
08redgt500 Posted August 5, 2008 Author Report Share Posted August 5, 2008 all gasses change density when temperature changes. this is described by the "ideal gas law" ... an equation that defines the relationship between Temperature, pressure and volume of a gas. here is linky: http://hyperphysics.phy-astr.gsu.edu/hbase...tic/idegas.html "Professor Bonedoc" out! You are correct BoneDoc. However, some change less and more slowly than other. Laws of Thermal Dynamics. Link to comment Share on other sites More sharing options...
08redgt500 Posted August 5, 2008 Author Report Share Posted August 5, 2008 +1 on what Professor BoneDoc said. A Nobel Gas is inert under normal circumstances because its outer valence shell, (layer of electrons), is full already, but they will expand/contract according to temperature. I had no idea so many physics majors owned these vehicles. What a bright bunch of people we are. Link to comment Share on other sites More sharing options...
tekheavy Posted August 5, 2008 Report Share Posted August 5, 2008 I filled my tires with helium. Car really flies now!!! Link to comment Share on other sites More sharing options...
08redgt500 Posted August 5, 2008 Author Report Share Posted August 5, 2008 Costco and its free. Very kewl. Costco is my second drug.....I can't go in there w/o walking out considerably lighter in the wallet. Thanks! Link to comment Share on other sites More sharing options...
08redgt500 Posted August 5, 2008 Author Report Share Posted August 5, 2008 I filled my tires with helium. Car really flies now!!! :hysterical: :hysterical: Link to comment Share on other sites More sharing options...
str8black500 Posted August 5, 2008 Report Share Posted August 5, 2008 Never thought id see thermo dynamics mentioned here... man i loved that class! Link to comment Share on other sites More sharing options...
CH53Driver Posted August 5, 2008 Report Share Posted August 5, 2008 I figure if it's good enough for my helicopter (nitrogen in the tires that is) then it's good enough for my GT500! :happy feet: Oh yeah, since I live in VA right now where the temperature can change in 10 minutes I decided to do it since nitrogen is less affected by temperature changes than just plain old air! I haven't had any issues so far. Good info on COSTCO, didn't realize they did that service for free! I guess I need to become a member! :happy feet: Link to comment Share on other sites More sharing options...
69deluxe Posted August 6, 2008 Report Share Posted August 6, 2008 I filled my tires with helium. Car really flies now!!! Try argon in the back and leave the helium in the front to improve the f/r weight ratio. Link to comment Share on other sites More sharing options...
Boss Doctor Posted August 6, 2008 Report Share Posted August 6, 2008 I had no idea so many physics majors owned these vehicles. What a bright bunch of people we are. Chemistry here, and apparently not too bright because no one pointed out that Nitrogen isn't a noble gas: it's a mostly inert diatomic gas because of the triple bond between atoms. But it has been over a decade since I even looked at the periodic table. Link to comment Share on other sites More sharing options...
rsfdiver Posted August 6, 2008 Report Share Posted August 6, 2008 I filled my tires with helium. Car really flies now!!! Helium would leak out GAY-LUSSAC’S LAW P2 = P1 x T2/T1 P1 initial pressure absolute. P2 final pressure absolute. T1 initial temp absolute. T2 final temp absolute. I think all gases expand and contract due to temperature and or pressure. Where say water, as a liquid, is supposedly not compressible. Link to comment Share on other sites More sharing options...
KCMO-GT500 Posted August 6, 2008 Report Share Posted August 6, 2008 Helium would leak out GAY-LUSSAC’S LAW P2 = P1 x T2/T1 P1 initial pressure absolute. P2 final pressure absolute. T1 initial temp absolute. T2 final temp absolute. I think all gases expand and contract due to temperature and or pressure. Where say water, as a liquid, is supposedly not compressible. the equation is correct; or we could use the ol' PV=nRT here is a good article discussing the pros and cons from the wall street journal link biggest pro seems to be the slower loss of nitrogen through the rubber, since it is a larger molecule; but here is what someone else had to say about that Nitrogen proponents say that the nature of the gas means it's less prone to leaking out over time through the pores present in rubber tires. But most air leakage in tires can be traced to poor fit around the rim of the wheel or the valve stem, rather than gas permeating through the rubber. but it certainly won't hurt to use it if it makes you feel better. Link to comment Share on other sites More sharing options...
old guy Posted August 6, 2008 Report Share Posted August 6, 2008 It's my understanding that nitrogen contains less moisture which helps prevent wheel deterioration and keeps the sensors in newer cars in better shape. Also, as stated above, the molecules are fatter so there is less air loss due to seepage. But the consensus seems to be that it really doesn't do much, if anything. Link to comment Share on other sites More sharing options...
rpretzel Posted August 6, 2008 Report Share Posted August 6, 2008 all gasses change density when temperature changes. this is described by the "ideal gas law" ... an equation that defines the relationship between Temperature, pressure and volume of a gas. here is linky: http://hyperphysics.phy-astr.gsu.edu/hbase...tic/idegas.html "Professor Bonedoc" out! +1 Ah yes. The ol' PV=nRT formula. Something I'll never forget from high school chem & physics. Link to comment Share on other sites More sharing options...
DubbsFaris Posted August 6, 2008 Report Share Posted August 6, 2008 Chemistry here, and apparently not too bright because no one pointed out that Nitrogen isn't a noble gas: it's a mostly inert diatomic gas because of the triple bond between atoms. But it has been over a decade since I even looked at the periodic table. In that case, you might be blown away to find out that the entire chart is now filled in! Seriously, I was in high school in the mid 80's and there were two lines of the periodic table still blank... I took a science class in college in 2004 for work, and they had a new table up. I was flipping out!! How did this NOT make world news? Isn't that news worthy information? Maybe it was just a big deal to me, but the rest of the class thought I was just disrupting!! (at least they were laughing and not calling me an old phogie) Link to comment Share on other sites More sharing options...
BoneDoc Posted August 6, 2008 Report Share Posted August 6, 2008 I must say that I am constantly IMPRESSED with the breadth of knowledge on this site. being a former engineer my self (now a bone doctor) I can barely remember any of this stuff.... kudos to all of you. Link to comment Share on other sites More sharing options...
moabman Posted August 6, 2008 Report Share Posted August 6, 2008 I have been using a custom blend of 79% Nitrogen, 20.9% oxygen and .1% other trace gases for years and have had pretty good results. :happy feet: Link to comment Share on other sites More sharing options...
rpretzel Posted August 6, 2008 Report Share Posted August 6, 2008 I have been using a custom blend of 79% Nitrogen, 20.9% oxygen and .1% other trace gases for years and have had pretty good results. :happy feet: Me too. And I found a source where I can get it for FREE!!!! :happy feet: Answer me this... If Nitrogen doesn't leak out because it's a bigger molecule, that means the other gasses that make up the air we breath must be leaking out...thus the advantage of pure nitrogen vs. the air we breath. Wouldn't that seem to indicate that, over time, as you top off your tire pressure, eventually the content of your tires would be nearly 100% nitrogen because the non-nitrogen gasses are leaking out and you are replenishing it with a 79% nitrogen gas? Buying nitrogen for your tires is a waste of $$$$. Link to comment Share on other sites More sharing options...
CH53Driver Posted August 6, 2008 Report Share Posted August 6, 2008 Buying nitrogen for your tires is a waste of $$$$. So then why does the aviation and racing industries use it? Link to comment Share on other sites More sharing options...
moabman Posted August 6, 2008 Report Share Posted August 6, 2008 The process of generating pure nitrogen eliminates moisture which may or may not be removed from compressed air. In addition, it eliminates the oxygen which causes oxidation damage to rubber even when it is formulated using anti-oxidants in the rubber. Nitrogen in race car tires Link to comment Share on other sites More sharing options...
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