nitrogen in tires

Just purged my tires and filled with nitrogen. Has anyone else done this? Supposed to give consistent tire pressure, cooler tire temps, and longer life.
http://nitrogendirect.com

Welcome fellow Texan. I've heard of using it and helium in track bicycles for racing purposes but not for everyday use. Are cooler tires on a motorcycle really a good idea?

NITROGEN. approximately 69% of our daily air. ever seen a dragster do a big burnout just before the race. the cold tires go from air temp to several hundred degrees in seconds. if he had "air" the tires they would expand and blow up. airplane leaves LAX at 60 degrees and lands in michigan at minus 20 on flat tires! how 'bout the space shuttle. tires inflated to proper pressure and goes into space (cold) and returns thru the atmoshere to land on properly infated tires! bottom line is UNLESS you are talking major heat or alttiude changes you get no benefit from nitrogen and i suspect all the tire (racing or street) manufactors use air in r&d or they would lable the tires for nitrogen use. COSTCO has recently started using nitrogen in tires as a sales gimmick. i work for a leading "gas" company and could get all the nitrogen i want at cost and see no benefit.
my biggest pet peeve is the selling of co2 inflatetors for tires at our motorcycle supply shops. this is probably worse than using compressed natural gas! there is also no benefit to using helium. happy to answer all "gas questions"

Thanks for the info VFR FLYER. I have a gas question. Why does helium make your voice funny for a few seconds afer you inhale it?

quicknick, Feb 18 2006, 11:57 AMThanks for the info VFR FLYER. I have a gas question. Why does helium make your voice funny for a few seconds afer you inhale it?

don't know, don't care BUT...........

any time you breath anything but air or oxygen you deprive your brain of needed oxygen and the resulting deaths may be found from the Compressed Gas Association. at or about $100 for a 220 cu in. tank are you letting your employees or customers do this? hope not! your liable!!!!!!!!!!!!!!

quicknick, Feb 18 2006, 12:57 PMThanks for the info VFR FLYER. I have a gas question. Why does helium make your voice funny for a few seconds afer you inhale it?

The speed of sound in air is about 350m/s. The speed of sound in helium is about 900m/s, so your vocal cords will resonate about 2.5 times higher than with normal air.

This is kind of off the subject, but FLYER see if you agree. For every 10 degrees of ambient temp change, there is 1 psi difference in the tire. Therefore if you inflate your tire to 36 psi at 0 deg F, and the temp rose to 100 deg F, your tire would then have 46 psi in it. That is the rule of thumb that I have lived by for as long as I can remember, is this correct.

VFR FLYER, Feb 18 2006, 07:24 PMdon't know, don't care BUT...........

any time you breath anything but air or oxygen you deprive your brain of needed oxygen and the resulting deaths may be found from the Compressed Gas Association. at or about $100 for a 220 cu in. tank are you letting your employees or customers do this? hope not! your liable!!!!!!!!!!!!!!

Well, sort of. The main reason we breathe is to purge the carbon dioxide we've built up. Getting the oxygen is a secondary benefit. This is why the air that we breathe out still contains about 16% oxygen, when the air we breathe in has about 20%. I don't recommend seeing how long you can breathe air without oxygen, but having fun with helium once in a while is unlikely to kill.

As mentioned above, helium is much lighter than any of the gas particles that make up the air we breathe. As such, it's a lot easier to move, and your vocal cords vibrate much more easily when passing helium over them as compared to air. The helium then vibrates at a higher frequency, and you talk like a chipmunk (animated, not the park kind).
Brian

chris2992, Feb 18 2006, 12:40 PMThis is kind of off the subject, but FLYER see if you agree. For every 10 degrees of ambient temp change, there is 1 psi difference in the tire. Therefore if you inflate your tire to 36 psi at 0 deg F, and the temp rose to 100 deg F, your tire would then have 46 psi in it. That is the rule of thumb that I have lived by for as long as I can remember, is this correct.

the three have to be used together....temp,,altitude..barametric pressure

your formula may work great at sea level and not too good in denver, co. at 5000+ feet

as a sportbike rider to and from work i check my air once a month or if the weather has changed a lot.
when i going to ride palomar mtn or any of the twisty's i check tire pressure before riding every time

what counts is what works for riding. if your concerned 'bout air .........then you must ride with both eyes open! happy riding to all..................... +1.gif

BDKesling, Feb 18 2006, 01:41 PMWell, sort of.  The main reason we breathe is to purge the carbon dioxide we've built up.  Getting the oxygen is a secondary benefit.  This is why the air that we breathe out still contains about 16% oxygen, when the air we breathe in has about 20%.  I don't recommend seeing how long you can breathe air without oxygen, but having fun with helium once in a while is unlikely to kill.

well if you want to nit-pic ...........the air we breathe in is to get oxygen (PRIMARY) dry.gif and the air we breathe out is to rid ourselves of carbon dioxide.

in the good ole usa several people DIE yearly from playing with helium and the person allowing this is liable. i didn't say it wasn't fun, i just don't do it

Chris, for most gases at near room temperature, the ideal gas law will hold, where PV=nRT. (pressure, volume, number of particles, the gas constant, and temperature). Temperature must be in Kelvin for this to work.

If the volume and number of gas particles don't change, (tire doesn't expand noticeably, and you don't have any leaks), then you can set up a relation of

P1/T1=P2/T2. If your initial pressure is 36 at 0 fahrenheit (http://www.convert-me.com/en/), that's 255.4 K. Going to 100 F (310.9 K), we can calculate the new pressure:

P2=P1T2/T1 = 43.8 psi.

That's my understanding of it, anyway goofy.gif
Brian

VFR FLYER, Feb 18 2006, 08:51 PMwell if you want to nit-pic ...........the air we breathe in is to get oxygen (PRIMARY) dry.gif and the air we breathe out is to rid ourselves of carbon dioxide.

in the good ole usa several people DIE yearly from playing with helium and the person allowing this is liable. i didn't say it wasn't fun, i just don't do it

I'll have to agree to disagree. Carbon monoxide poisoning doesn't hurt because we are still able to breathe out and get rid of the built up carbon dioxide, which I will contend is the primary reason for breathing huh.gif

I'm sure several people die playing with helium, but I won't agree that breathing it in and talking funny makes it dangerous anymore than I will agree that riding a motorcycle is dangerous because some idiot in a cage might not see you. Both CAN be dangerous, along with walking down a flight of stairs, but with my opposable thumbs and a skull full of kidneys, I'll take my chances.
Brian

ExcaliberVFR800ABS, Feb 18 2006, 12:40 PMJust purged my tires and filled with nitrogen. Has anyone else done this? Supposed to give consistent tire pressure, cooler tire temps, and longer life.
http://nitrogendirect.com

Have been an A&P Mechanic off/on for twenty years...on aircraft we use Nitrogen because it is "clean and dry"....the alum wheels will corrode with the moisture in shop air.
Just about everything expands with heat and contracts with cooler temps...there are some rare alloys that i have worked with that do the opposite...though. Am sure tour deFrance riders would use just about anything if they thought they would have an edge.
I work with some folks that have worked at "IR"...i would not believe anything they have come up with.
tom

BDKesling, Feb 18 2006, 02:00 PMI'll have to agree to disagree.  Carbon monoxide poisoning doesn't hurt because we are still able to breathe out and get rid of the built up carbon dioxide, which I will contend is the primary reason for breathing  huh.gif

I'm sure several people die playing with helium, but I won't agree that breathing it in and talking funny makes it dangerous anymore than I will agree that riding a motorcycle is dangerous because some idiot in a cage might not see you.  Both CAN be dangerous, along with walking down a flight of stairs, but with my opposable thumbs and a skull full of kidneys, I'll take my chances. 
Brian

IF YOU AGREE TO DISAGREE, ARE SAYING I AM INCORRECT ON THE TOPIC *NITROGEN IN TIRES?* WHATS YOUR ANSWER?

BDKesling, Feb 18 2006, 03:00 PMI'll have to agree to disagree.� Carbon monoxide poisoning doesn't hurt because we are still able to breathe out and get rid of the built up carbon dioxide, which I will contend is the primary reason for breathing� huh.gif

Carbon monoxide does hurt...and kill. Our hemoglobin attaches to carbon monoxide much more readily than oxygen. Its bonds to the hemoglobin are more than 200 times stronger than oxygen's. It prevents oxygen from getting into the blood even if you move out of the contaminated area into an oxygen rich environment. It takes considerable time for the carbon monoxide to be purged from your bloodstream even after you have been removed from the area of contamination.

Many firefighters have died over the years because of the cumulative effect of entering and re-entering burning structures and breathing carbon monoxide, even though they felt fine before going in that last time.

VFR FLYER, Feb 18 2006, 12:36 PMmy biggest pet peeve is the selling of co2 inflatetors for tires at our motorcycle supply shops. this is probably worse than using compressed natural gas! there is also no benefit to using helium. happy to answer all "gas questions"

My reference to helium in bicycle tires I read about was that they could get higher pressures in the tires with say helium as opposed to compressed air....ie less rolling resistance on a wooden track so it would be a benefit.

What exactly is your peeve about the co2 inflaters?

Nitrogen alone has a lower diffusivity through tire rubber than the other components of regular air. After switching to nitrogen, I've very rarely had to plus up the tires, and as people have mentioned, the pressure doesn't vary with temperature nearly as much.

Two years without, two years with, and I've noted that the nitrogen does deliver what it says it will. That being said, I got it for free with the tire installations. Since I don't think its a big deal to check and fill up my tires, I don't know that I'd go out of my way for it...

dutchinterceptor, Feb 18 2006, 02:18 PMWhat exactly is your peeve about the co2 inflaters?

C02 inflators are dangerous because..........co2 expands rapidly with temp as a gas or liquid. a common example is a common result ie. co2 cylnders are filled on the dock in las vegas. c02 pressure in the cylinder at 70 degrees is about 850 psi. the cylinder has a burst disc safety that releases a little above 2000 psi. the newly filled cylinders are rolled out in the yard for storage. in the summer at 110 degrees plus in the sun. several of the burst discs will let go....expanding volume.

i can demonstate this to the local people by taking a plastic soda bottle and squirting a little co2 inside and screw the cap down tight. throw the bottle out into the parking lot and within a few minutes the bottle will explode from the internal pressure. DO NOT DO THIS! the force of the explodeing bottle can remove your hand. you may also get a response from the fire dept and or police.
if you have an inflator fill a tube just enough to give it its shape and then set it in the sun. oh yeah! DO NOT DO THIS! ITS DANGEROUS

VFR FLYER, Feb 18 2006, 09:09 PMIF YOU AGREE TO DISAGREE, ARE SAYING I AM INCORRECT ON THE TOPIC *NITROGEN IN TIRES?* WHATS YOUR ANSWER?

VFRvflyer: The only thing I was disagreeing with was the primary reason for breathing, which is really a moot point.

Using compressed nitrogen will prevent any corrosion that might be caused by moisture or oxygen in the air, but it will not prevent a change in pressure due to a temperature change. If anything, nitrogen will more closely follow the pressure versus temperature relation I mentioned above, as nitrogen is a more ideal gas than air.

If I were concerned about corrosion, I would run nitrogen or argon (heavier than nitrogen, less chance of diffusion).

tbzep: When I say carbon monoxide poisoning doesn't hurt, I mean that it isn't a painful death, like drowning or suffocation, or getting hit with a big spear. This was in reference to our reasons for breathing.

Brian

VFR FLYER, Feb 18 2006, 03:47 PMC02 inflators are dangerous because..........co2 expands rapidly with temp as a gas or liquid. a common example is a common result ie. co2 cylnders are filled on the dock in las vegas. c02 pressure in the cylinder at 70 degrees is about 850 psi. the cylinder has a burst disc safety that releases a little above 2000 psi. the newly filled cylinders are rolled out in the yard for storage. in the summer at 110 degrees plus in the sun. several of the burst discs will let go....expanding volume.

i can demonstate this to the local people by taking a plastic soda bottle and squirting a little co2 inside and screw the cap down tight. throw the bottle out into the parking lot and within a few minutes the bottle will explode from the internal pressure. DO NOT DO THIS! the force of the explodeing bottle can remove your hand. you may also get a response from the fire dept and or police.
if you have an inflator fill a tube just enough to give it its shape and then set it in the sun. oh yeah! DO NOT DO THIS! ITS DANGEROUS

Just so I'm clear on this....you're saying that the cartridges are dangerous in and of themselves OR just that the CO2 gas is dangerous under certain conditions?

Are you saying that the cartridges have the potential for explosion while sitting in my jersey pocket while I'm cycling on a 100+ degree day? Might have to consider a frame pump if that's true.

BDKesling, Feb 18 2006, 03:58 PM
tbzep:  When I say carbon monoxide poisoning doesn't hurt, I mean that it isn't a painful death, like drowning or suffocation, or getting hit with a big spear.  This was in reference to our reasons for breathing.

True. You just get sleepy and take a nap forever.

dutchinterceptor, Feb 18 2006, 04:03 PMJust so I'm clear on this....you're saying that the cartridges are dangerous in and of themselves OR just that the CO2 gas is dangerous under certain conditions? 

Are you saying that the cartridges have the potential for explosion while sitting in my jersey pocket while I'm cycling on a 100+ degree day?  Might have to consider a frame pump if that's true.

I'd rather consider this CO2 pump...

[image: user posted image]

Well i thought i was saying not to use co2 in tires PERIOD! however the little cartriges are probably fairly safe unused i would not put a partially charged inflator anywhere but on my person.

what is the beer keg setup? i understand the bottle, keg but was is the pump for? a normal keg has co2 going in to pressure the keg and a beer supply out to tapper but that looks like some kind of pump? huh.gif

VFR FLYER, Feb 18 2006, 04:46 PM
what is the beer keg setup? i understand the bottle, keg but was is the pump for? a normal keg has co2 going in to pressure the keg and a beer supply out to tapper but that looks like some kind of pump? huh.gif

LOL! Here's a quote from the site. You can tell, English isn't their first language. It was the first interesting pic dealing with CO2 pressurization that I found doing a google image search. tongue.gif

KEGS FIZZING MACHINE art.490

to fizz the still wine.

It is consisting of a recirculating pump, a pressure reducing valve and a specific fizzer to joint carbon dioxide (CO2)  to the wine contained in the kegs.

To being under pressure in the keg, the wine do not lose the fizz.

tbzep, Feb 18 2006, 04:52 PMLOL!  Here's a quote from the site.  You can tell, English isn't their first language.  It was the first interesting pic dealing with CO2 pressurization that I found doing a google image search.  tongue.gif

i am confused? why would someone waste time trying to fizz wine? pour that crap out and get some good beer!

i apoligize for going off topic! (not for my commet)

where were we..............ahh yes nitrogen, one of the two gases used in production and pressurization of guiness and murphys beers..............

I heard from an tire maker a long time ago that nitrogen does not degrade the compounds in your tires as fast as oxygen and therefore would make your tires last longer. (ie longer period till tire has what i call weather cracking)

redneck7769, Feb 18 2006, 06:06 PMI heard from an tire maker a long time ago that nitrogen does not degrade the compounds in your tires as fast as oxygen and therefore would make your tires last longer. (ie longer period till tire has what i call weather cracking)

thats true...........your tire will not weather crack on the inside where the nitrogen is............

if your worried about weather cracking on the outside of your sportbike tires................either start ridin it or...................most guys i know replace worn out tires every two years...........we try and wear out the whole tire tongue.gif

VFR FLYER, Feb 18 2006, 06:13 PMi am confused? why would someone waste time trying to fizz wine? pour that crap out and get some good beer!

I guess they want to make instant (fake) Champaigne without the second fermentation process. I had never heard of it before finding it in my search earlier today.

VFR FLYER, Feb 18 2006, 10:47 PMC02 inflators are dangerous because..........co2 expands rapidly with temp as a gas or liquid. a common example is a common result ie. co2 cylnders are filled on the dock in las vegas. c02 pressure in the cylinder at 70 degrees is about 850 psi. the cylinder has a burst disc safety that releases a little above 2000 psi. the newly filled cylinders are rolled out in the yard for storage. in the summer at 110 degrees plus in the sun. several of the burst discs will let go....expanding volume.

Anyone bought that airbag jacket? tongue.gif

We used Nitrogen when racing in Hawaii. Air has other gases in it and some of those expand due to heat, and contract due to cold. Nitrogen was chosen because it is inert and readily available. Being inert, it did not change the tire preasure when the tires heated up while racing. Just my $0.02, without any tangents.

I have a gas question. How to neutralize the ass gas that I try to pass off on the dog? Oops, we don't have a dog. laugh.gif

Matches just mask things. goofy.gif

VFR4Lee, Feb 18 2006, 08:56 PMI have a gas question. How to neutralize the ass gas that I try to pass off on the dog? Oops, we don't have a dog.  laugh.gif

Matches just mask things.  goofy.gif

That can kill brain cells you know!! goofy.gif

Growler67, Feb 18 2006, 06:53 PMWe used Nitrogen when racing in Hawaii.  Air has other gases in it and some of those expand due to heat, and contract due to cold.  Nitrogen was chosen because it is inert and readily available.  Being inert, it did not change the tire preasure when the tires heated up while racing.  Just my $0.02, without any tangents.

SORRY! must have had to much geritol for breakfast. turned 55 last sat. so i guess i have a lot to SHARE!
if your refering to the track on oahu, hawaii then i am sure you have a lot to share. like having nitrogen to race on, but no shade. no place to sit except the grandstands or your vehicle. no emergeny vehicle (working condition) or personnel. flies everywhere. bathrooms scary and twice as bad if you couldn't hold your breath long enough. when the bikes ran, everyone is locked into the center field area (padlocked inside chainlink fencing). in the summer when we were there it was as hot as the great mojave desert where i grew up! and that ain't even half of it. tangets aside, your right.......nitrogen is better.................

Growler67, Feb 18 2006, 08:53 PMWe used Nitrogen when racing in Hawaii.  Air has other gases in it and some of those expand due to heat, and contract due to cold.  Nitrogen was chosen because it is inert and readily available.  Being inert, it did not change the tire preasure when the tires heated up while racing.  Just my $0.02, without any tangents.

not true. nitrogen will expand with heat. standard tire pressure at 70 deg in a 767 is supposed to be 205 psi. after one landing the tire pressure may raise to as high as 240 psi. that is just one landing. nitrogen will expand, but not at as high of coefficient as outside air.
i was also taught you loose pressure with nitrogen faster than air through tire permeability due to nitrogen being a smaller atom.
secondly and probably most important is nitrogen is used in aircraft tires due to it non flamibility. tires get hot fast and can burn. the wheels are made of magnesium in most cases. you would not want a large volume of oxygen released in a fire enviroment should a 4 1/2 tall tire let loose.

As heavy as a VFR might be in comparison to other bikes, it doesn't weigh what a 767 does. The amount of increase in negligeble compared to the same tires under the same conditions filled with air. A front tire was set at 32 psi with air and after a few laps, it was up to almost 36 psi. We switched to nitrogen for an endurance race and after 30 laps it was still at the original pressure. The others that had air were making adjustments, we just topped off the fuel and switched riders.

I think the reason they use nitrogen in race applications is that you can predict the change in pressure due to heat because it is moisture free. The moisture in regular air is what screws up the pressure when heated.

Nitrogen was used in my jet's tires for the reasons stated and others:

1) It's dry and won't allow moisture or salt to corrode the insides of the rims.
2) It has predictable inflation characteristics, being from a controlled bottle vice compressed sea air (which will also have traces of compressor lubricating oil). If one tire goes flat, the mechs will be able to eliminate one variable troubleshooting the loss of pressure.
3) It is inflamable. Not such a big deal in the tire itself, but the ship a)needs to minimize the number of flamable gas tanks aboard, and cool.gif

However, nitrogen, like any gas, inert, noble, mixed, flamable, or otherwise, obeys the same laws of physics as all of them do: PV=NRT. If you're looking to improve your bike's performance by putting pure nitrogen in the tires, you'd probably do better spending your money shaving five lbs. (1%) of weight somewhere.

BDKesling, Feb 18 2006, 02:41 PMWell, sort of.  The main reason we breathe is to purge the carbon dioxide we've built up.  Getting the oxygen is a secondary benefit.  This is why the air that we breathe out still contains about 16% oxygen, when the air we breathe in has about 20%.  I don't recommend seeing how long you can breathe air without oxygen, but having fun with helium once in a while is unlikely to kill.

As mentioned above, helium is much lighter than any of the gas particles that make up the air we breathe.  As such, it's a lot easier to move, and your vocal cords vibrate much more easily when passing helium over them as compared to air.  The helium then vibrates at a higher frequency, and you talk like a chipmunk (animated, not the park kind).
Brian

And, VFR FLYER thought he was the gas guy! Ha!

Growler67, Feb 18 2006, 11:01 PMAs heavy as a VFR might be in comparison to other bikes, it doesn't weigh what a 767 does.  The amount of increase in negligeble compared to the same tires under the same conditions filled with air.  A front tire was set at 32 psi with air and after a few laps, it was up to almost 36 psi.  We switched to nitrogen for an endurance race and after 30 laps it was still at the original pressure.  The others that had air were making adjustments, we just topped off the fuel and switched riders.

i wasnt doubting the fact you had minimal change of pressure in a vessle as small as a bike tire. im just correcting the fact that nitrogen too will change pressure with heat. wether you feel you had no pressure change in your tires you in fact did, but the volume was such that it was a negligable difference.

for street use the use of nitrogen is a pure sales gimmick. the heat generated by normal riding doesnt justify the cost.

All formula 1 and NASCAR teams use nitrogen in there tires as well. Rumor has it they wont leak as quickly as oxygen and tire pressure raminas constant. Nitrogen is 3 times more dense than air so you don't have to worry about slow leaks.


Here was a good article on it.
Nitrogen is also supposed to move through tire rubber three times more slowly. Without any impurities, nitrogen also is subject to less expansion and contraction as the tire heats up and cools down during usage.

Regularly checking the air pressure in your tires is one of the most important parts of maintaining the safety of any vehicle, though many people never bother to do it. Keeping tire pressure at its proper level also dramatically improves fuel economy.

The air we breathe is about 79% nitrogen, with oxygen, carbon dioxide and other gases making up the balance. But the small amount of oxygen makes a big difference, obviously. Oxygen is highly active, causing corrosion and aging in many different types of material. By contrast, nitrogen is an inert gas, making it ideal as a filling medium where you want to retard corrosion.

It may seem like a gimmick, but nitrogen has long been used as a filling medium in the racing circuit, the military and the airline industry. But they have traditionally used bottled compressed nitrogen, which is far too exotic and expensive for tire retailers.

Nitrogen began making its first appearance on the U.S. retail market in a small way in recent years, but it took off last year as major compressor manufacturers introduced low cost systems for retailers.

Ingersoll-Rand, the nation's largest manufacturer of large compressors, introduced a system for retailers about a year ago. Other systems are on the market from smaller manufacturers, as well.

Rather than using bottled nitrogen, the Ingersoll-Rand system and others like it use membrane filters to remove the other gases from the air. It also uses three filters with charcoal and coal to remove water and oil from the gas.

"When we first began talking about this a year and a half ago, people thought it was a joke," said Ryan Lang, Ingersoll-Rand's marketing manager for the system. "Now people say it is inevitable."

So far, a tiny percentage of the tens of thousands of tire retailers in the nation are offering it. The biggest chain to jump on the nitrogen bandwagon is Costco, the discount retailer. Several other major retailers are testing the systems.

The tire industry has endorsed the system. Goodyear and Michelin have issued technical service bulletins to their retailers saying that the use of nitrogen is acceptable and good practice.

i think i am going to use radon gas. not good for the lungs but i bet it would be great in a race tire

seriously, how much do we worry about corrosion on the inside of our wheels? how many have dismounted a tire and went "wow....look at the corrosion" its a non issue for a daily driver. nitrogen has benefits i dont deny, but not for the average consumer. how often do you need to service tires? once every 3 weeks? so you can go 4 with nitrogen...is it worth it?

Thanks for you responses. The Lexus dealership I work at just received the nitrogen machine so it was no cost to me. Not that many of us have chrome wheels, the inside of chrome wheels do corrode causing air to leak at the bead. I plan on changing all my vehicles to nitrogen, probably will have to pay cost since I used my VFR for "training" it was free.

VFR FLYER, Feb 18 2006, 08:14 PMthats true...........your tire will not weather crack on the inside where the nitrogen is............

if your worried about weather cracking on the outside of your sportbike tires................either start ridin it or...................most guys i know replace worn out tires every two years...........we try and wear out the whole tire tongue.gif

Well I personally replace tires about once a year and weather cracking is not a problem. I was just stating a fact that was passed on to me. dry.gif

scooter996, Feb 19 2006, 09:10 PMRumor has it they wont leak as quickly as oxygen and tire pressure raminas constant. Nitrogen is 3 times more dense than air so you don't have to worry about slow leaks.
Here was a good article on it.
Nitrogen is also supposed to move through tire rubber three times more slowly. Without any impurities, nitrogen also is subject to less expansion and contraction as the tire heats up and cools down during usage.

This is not true in any way shape or form. Nitrogen is diatomic, meaning that nitrogen gas is two nitrogen atoms stuck together. Check the periodic table and you'll see the average atomic weight of nitrogen is 14.0067 atomic mass units, so a nitrogen molecule weighs 28.0134 atomic mass units, and a mole of nitrogen (that's 6.0220x10^24 nitrogen molecules) weighs 28.0134 grams. Diatomic oxygen (02, the stuff we get to breathe in after we expel our carbon dioxide tongue.gif ) weighs 32 grams per mole. Nitrogen and oxygen both behave as ideal gases, and at atmospheric pressure one mole of an ideal gas occupies 22.4 liters.

Now, air is about 80% nitrogen, and about 20% oxygen (if you want specifics, then 78.084% nitrogen, 20.947% oxygen, .934% argon, .033% carbon dioxide, and the rest made up in parts per million of neon, helium, krypton, sulfur dioxide, methane, hydrogen, nitrous oxide and a few others). If air is 80% nitrogen, and 20% oxygen, and if oxygen is heavier than nitrogen, then I would like to see a calculation showing how pure nitrogen can possibly be more dense than a mixture of nitrogen and a heavier gas!

The way I would go about calculating a density is I would say that since 1 mole = 22.4 liters, and nitrogen gas is 28.0134 grams/mol, then the density of nitrogen gas (in grams per liter) is 1.25.

If air is 80% nitrogen by mass and 20% oxygen by mass, then 100 grams of air will contain 80 grams of nitrogen, which is 2.86 moles (given 28.0134g/mol). The 20 grams of oxygen in our sample equates to .625 mol of O2 (given 32g/mol). If we want the density of air, then we find the grams per liter. We assumed 100grams of air, and we see that 100 grams of air contains 2.86 mol of N2 and .625 mol of O2, and we know that 2.86 + .625 = 3.49 mol of gas. Knowing that 22.4 Liters = 1 mol, we can calculate that we have 78.18 Liters of air if we have 100 grams of air, and so the density of air is 1.28.

Air is more dense than nitrogen, because 1.28 g/L is more dense than 1.25 g/L, and there is certainly not a difference of a factor of 3. Nitrogen will be SLIGHTLY more susceptible to expansion and contraction than dry air. If the air has moisture in it, then the increased heat capacity of the contained water molecules will screw with your expansion/contraction due to heat.

Oxygen gas and water can both act to corrode a metal wheel, which may lead to a leak, which would require topping the air off more often. Use nitrogen if you're worried about this.

Hell, you can use nitrogen all you want, I'm certainly not the nitrogen police. You can also sleep on a bed of magnets and drink "demagnetized" water. For that matter, replace all your bliker fluid with demagnetized water and watch your bike float 3 inches off the ground. But for the love of Interceptors, don't say that nitrogen gas doesn't expand and contract with heat or diffuse as quickly as oxygen.

If anyone wants to know or see more about this, drop me an email, swing by West Virginia University, and I'll fill some balloons with pure oxygen, pure nitrogen, argon, hydrogen, carbon dioxide, helium, and whatever else I can find a tank of. We'll pour liquid nitrogen on the balloons, watch them shrink, then watch them get bigger as they warm back up. Then we'll light the oxygen and hydrogen balloons to make big fireballs, inhale the helium balloon and talk funny, pour the carbon dioxide balloon into a beaker and use it to put out a candle, and rub the other balloons on our heads and stick them to the wall. Then I'll buy you a beer and we'll talk about oil. goofy.gif
Brian

BDK, you must be loads of fun at parties!! goofy.gif

767fixer, Feb 19 2006, 08:37 PMfor street use the use of nitrogen is a pure sales gimmick.

That's what I thought too when Costco started offering it in their tire shops.

But I find my car/truck/van tires don't need refilling nearly as often when they are inflated with nitrogen. I have to top off the tires maybe once every 6 to 8 months when they are filled with nitrogen vs. once very 2 to 3 months when they are filled with air.

Here's scientific confirmation of my experience LoL http://www.usc.edu/CSSF/Current/Projects/J0529.pdf

Dad out.

BDKesling, Feb 19 2006, 09:43 PMHell, you can use nitrogen all you want, I'm certainly not the nitrogen police.� You can also sleep on a bed of magnets and drink "demagnetized" water.� For that matter, replace all your bliker fluid with demagnetized water and watch your bike float 3 inches off the ground.� But for the love of Interceptors, don't say that nitrogen gas doesn't expand and contract with heat or diffuse as quickly as oxygen.

If anyone wants to know or see more about this, drop me an email, swing by West Virginia University, and I'll fill some balloons with pure oxygen, pure nitrogen, argon, hydrogen, carbon dioxide, helium, and whatever else I can find a tank of.� We'll pour liquid nitrogen on the balloons, watch them shrink, then watch them get bigger as they warm back up.� Then we'll light the oxygen and hydrogen balloons to make big fireballs, inhale the helium balloon and talk funny, pour the carbon dioxide balloon into a beaker and use it to put out a candle, and rub the other balloons on our heads and stick them to the wall.� Then I'll buy you a beer and we'll talk about oil.� goofy.gif
Brian

ROTFLMAO. Was that extemporaneous? lurk.gif No matter, after that, I'll buy. beer.gif

Just a interesting side note Scuba divers commonly breathe mixtures of Oxygen and helium and nitrogen for technical diving:

* Air is a mixture of 21% oxygen, 78% nitrogen, and approximately 1% other trace gases; to simplify calculations this last 1% is usually treated as if it were nitrogen. Being cheap and simple to use, it is the most common diving gas. As its nitrogen component causes nitrogen narcosis it has a safe depth limit of 40 metres (130 feet) for most divers.
* Pure oxygen is mainly used to speed the shallow decompression stops at the end of a technical dive. It was much used in frogmen's rebreathers.
* Nitrox is a mixture of oxygen and air, and generally refers to mixtures which are more than 21% oxygen. It is mainly used instead of air to accelerate decompression or to decrease the risk of Decompression sickness.
* Trimix is a mixture of oxygen, nitrogen and helium and is often used during the deep phase of a technical dive.
* Heliox is a mixture of oxygen and helium and is often used in the deep phase of a commercial deep dive.
* Heliair is a mixture of oxygen, nitrogen, and helium. It is suitable for in the deep phase of a technical dive. Blended from helium and air, it always has a 21:79 ratio of oxygen to nitrogen; the balance of the mix is helium.
* Hydreliox is a mixture of oxygen, helium, and hydrogen and is used for dives below 130 metres.
* Neox is a mixture of oxygen and neon sometimes employed for technical dives. It is rarely used due to its cost.


Stolen from: http://en.wikipedia.org/wiki/Breathing_gas

vfrjim2002, Feb 20 2006, 03:55 AMROTFLMAO. Was that extemporaneous?  lurk.gif   No matter, after that, I'll buy.  beer.gif

Sorry, I had to look up extemporaneous... yes it was, but I did use a calculator, and I checked my periodic table to make sure nitrogen was 14.0067 (others do vary a little) goofy.gif I may use this stuff as a bonus question at some point,
Brian

i love this thread!!!!! i cant wait for the thread on water types for radiators! distilled vs. tap vs. bottled spring. stay tuned!