Nitrogen Fill
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Joined: Jul 2007
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From: London
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Same as oem recommended tyre pressure when tyres are cold. I now always use Nitrogen it just makes me feel better when at 190mph+. :-).
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Joined: Feb 2005
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The question about nitrogen in tires has come up in other lists on the web as well.
1. Air is 78% nitrogen, N2, and 21% oxygen, O2. So even if you put air in the tire, it's already 78% nitrogen. Many of the so called nitrogen generators don't produce much more than 90% nitrogen.
2. At relatively low pressures (ie tire pressures) N2, O2 and water vapor will all behave as ideal gases, and follow PV=nRT. Pressure will increase or decrease to the same extent as the temperature increases or decreases regardless of which gas is in the tire. (Even at 300 psi, which is about 20 atm, there is little deviation from ideality.) Therefore the comments about N2 not changing in pressure as the temperature changes are without merit.
3. The rate of effusion (or diffusion) of a gas through a porous membrane depends on the molar mass and to some degree on the molecular diameter. N2 and O2 are almost the same size and N2 is lighter than O2 (28 g/mol vs 32 g/mol) so if either gas were to effuse out of the tire, nitrogen would do it more quickly. Luckily, tires are designed not to be porous membranes.
4. N2 and O2 both have essentially the same specific heat capacity, about 1.0 J/gK, and thermal conductivity, about 0.00026 W/cmK. Water vapor has a specific heat capacity of about 2 J/gK. But remember, water vapor will constitute less than 1% of the air in the tire. So the idea that N2 has different heat handling properties is also without merit.
5. The ozone, O3, in the atmosphere, which is a ground level pollutant, will do a great deal more damage to your tires than the O2 inside the tire. For instance, don't leave a condom out in the air in Los Angeles for a few days. It will develop lots of tiny holes and weaken.
1. Air is 78% nitrogen, N2, and 21% oxygen, O2. So even if you put air in the tire, it's already 78% nitrogen. Many of the so called nitrogen generators don't produce much more than 90% nitrogen.
2. At relatively low pressures (ie tire pressures) N2, O2 and water vapor will all behave as ideal gases, and follow PV=nRT. Pressure will increase or decrease to the same extent as the temperature increases or decreases regardless of which gas is in the tire. (Even at 300 psi, which is about 20 atm, there is little deviation from ideality.) Therefore the comments about N2 not changing in pressure as the temperature changes are without merit.
3. The rate of effusion (or diffusion) of a gas through a porous membrane depends on the molar mass and to some degree on the molecular diameter. N2 and O2 are almost the same size and N2 is lighter than O2 (28 g/mol vs 32 g/mol) so if either gas were to effuse out of the tire, nitrogen would do it more quickly. Luckily, tires are designed not to be porous membranes.
4. N2 and O2 both have essentially the same specific heat capacity, about 1.0 J/gK, and thermal conductivity, about 0.00026 W/cmK. Water vapor has a specific heat capacity of about 2 J/gK. But remember, water vapor will constitute less than 1% of the air in the tire. So the idea that N2 has different heat handling properties is also without merit.
5. The ozone, O3, in the atmosphere, which is a ground level pollutant, will do a great deal more damage to your tires than the O2 inside the tire. For instance, don't leave a condom out in the air in Los Angeles for a few days. It will develop lots of tiny holes and weaken.
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Joined: Jul 2003
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From: Walnut Creek, CA
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Being in the tire business before I'm actually AMAZED by how many tire shops are now offering nitrogen fills. I even had a few customers who ONLY USED nitrogen. Seems like it's catching on more and more.
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Joined: Sep 2007
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From: SF Bay Area
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The question about nitrogen in tires has come up in other lists on the web as well.
1. Air is 78% nitrogen, N2, and 21% oxygen, O2. So even if you put air in the tire, it's already 78% nitrogen. Many of the so called nitrogen generators don't produce much more than 90% nitrogen.
2. At relatively low pressures (ie tire pressures) N2, O2 and water vapor will all behave as ideal gases, and follow PV=nRT. Pressure will increase or decrease to the same extent as the temperature increases or decreases regardless of which gas is in the tire. (Even at 300 psi, which is about 20 atm, there is little deviation from ideality.) Therefore the comments about N2 not changing in pressure as the temperature changes are without merit.
3. The rate of effusion (or diffusion) of a gas through a porous membrane depends on the molar mass and to some degree on the molecular diameter. N2 and O2 are almost the same size and N2 is lighter than O2 (28 g/mol vs 32 g/mol) so if either gas were to effuse out of the tire, nitrogen would do it more quickly. Luckily, tires are designed not to be porous membranes.
4. N2 and O2 both have essentially the same specific heat capacity, about 1.0 J/gK, and thermal conductivity, about 0.00026 W/cmK. Water vapor has a specific heat capacity of about 2 J/gK. But remember, water vapor will constitute less than 1% of the air in the tire. So the idea that N2 has different heat handling properties is also without merit.
5. The ozone, O3, in the atmosphere, which is a ground level pollutant, will do a great deal more damage to your tires than the O2 inside the tire. For instance, don't leave a condom out in the air in Los Angeles for a few days. It will develop lots of tiny holes and weaken.
1. Air is 78% nitrogen, N2, and 21% oxygen, O2. So even if you put air in the tire, it's already 78% nitrogen. Many of the so called nitrogen generators don't produce much more than 90% nitrogen.
2. At relatively low pressures (ie tire pressures) N2, O2 and water vapor will all behave as ideal gases, and follow PV=nRT. Pressure will increase or decrease to the same extent as the temperature increases or decreases regardless of which gas is in the tire. (Even at 300 psi, which is about 20 atm, there is little deviation from ideality.) Therefore the comments about N2 not changing in pressure as the temperature changes are without merit.
3. The rate of effusion (or diffusion) of a gas through a porous membrane depends on the molar mass and to some degree on the molecular diameter. N2 and O2 are almost the same size and N2 is lighter than O2 (28 g/mol vs 32 g/mol) so if either gas were to effuse out of the tire, nitrogen would do it more quickly. Luckily, tires are designed not to be porous membranes.
4. N2 and O2 both have essentially the same specific heat capacity, about 1.0 J/gK, and thermal conductivity, about 0.00026 W/cmK. Water vapor has a specific heat capacity of about 2 J/gK. But remember, water vapor will constitute less than 1% of the air in the tire. So the idea that N2 has different heat handling properties is also without merit.
5. The ozone, O3, in the atmosphere, which is a ground level pollutant, will do a great deal more damage to your tires than the O2 inside the tire. For instance, don't leave a condom out in the air in Los Angeles for a few days. It will develop lots of tiny holes and weaken.
Now that is an analysis that makes sense to me! Thanks.
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Joined: Jan 2006
Posts: 128
From: stuttgart, germany
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For everyday use and car guys who watch /rotate/ maintain their tires probably very little in difference, but at the track I notice large difference in tire pressure. And it is a pain in the a-- when you have nitrogen in your tires and months later you have to squirt air in it cuz no nitro around. I have paid for nitro at tire shops but I usually can get my tire fill at my work.
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Joined: Jul 2003
Posts: 401
From: Huntington Beach, California
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Gentlemen, a practical point. If you go to a gas station for compressed air, hold the nozzle at the ground and blow out some air. You will be amazed at the amount of water in the line. Same with home systems. Compressed air, temperature and low points will trap a LOT of water. At my plant we go to great lengths to get moisture out of our high and low pressure compressed air systems. The water in the compressed air will accelerate corrosion on surfaces susceptible to corrosion (rust). Nitrogen is more stable a mix than chemically than air. Having said all of this I use a home air compressor and make sure to drain the system from time to time. But Nitrogen is used in aircraft, that should tell you something.....I don't think it'd cost all that much to get a bottle of nitrogen and a regulator and use it to fill your tires. Maybe I'll explore this.
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From: N. California
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Bingo.
Nitrogen like air, expands when heated.
Technical pure nitrogen, in a bottle, may have less water vapor, and therefore may behave better...BUT THAT IS NOT WHAT SHOPS TRY TO SELL YOU.
THis whole myth of nitrogen fill has been perpetrated by manufacturers of nitrogen generator equipment for tire stores.
Scam- unless your are buying 99.99+% bottled dry nitrogen. For that matter use any gas!
Nitrogen like air, expands when heated.
Technical pure nitrogen, in a bottle, may have less water vapor, and therefore may behave better...BUT THAT IS NOT WHAT SHOPS TRY TO SELL YOU.
THis whole myth of nitrogen fill has been perpetrated by manufacturers of nitrogen generator equipment for tire stores.
Scam- unless your are buying 99.99+% bottled dry nitrogen. For that matter use any gas!
The question about nitrogen in tires has come up in other lists on the web as well.
1. Air is 78% nitrogen, N2, and 21% oxygen, O2. So even if you put air in the tire, it's already 78% nitrogen. Many of the so called nitrogen generators don't produce much more than 90% nitrogen.
2. At relatively low pressures (ie tire pressures) N2, O2 and water vapor will all behave as ideal gases, and follow PV=nRT. Pressure will increase or decrease to the same extent as the temperature increases or decreases regardless of which gas is in the tire. (Even at 300 psi, which is about 20 atm, there is little deviation from ideality.) Therefore the comments about N2 not changing in pressure as the temperature changes are without merit.
3. The rate of effusion (or diffusion) of a gas through a porous membrane depends on the molar mass and to some degree on the molecular diameter. N2 and O2 are almost the same size and N2 is lighter than O2 (28 g/mol vs 32 g/mol) so if either gas were to effuse out of the tire, nitrogen would do it more quickly. Luckily, tires are designed not to be porous membranes.
4. N2 and O2 both have essentially the same specific heat capacity, about 1.0 J/gK, and thermal conductivity, about 0.00026 W/cmK. Water vapor has a specific heat capacity of about 2 J/gK. But remember, water vapor will constitute less than 1% of the air in the tire. So the idea that N2 has different heat handling properties is also without merit.
5. The ozone, O3, in the atmosphere, which is a ground level pollutant, will do a great deal more damage to your tires than the O2 inside the tire. For instance, don't leave a condom out in the air in Los Angeles for a few days. It will develop lots of tiny holes and weaken.
1. Air is 78% nitrogen, N2, and 21% oxygen, O2. So even if you put air in the tire, it's already 78% nitrogen. Many of the so called nitrogen generators don't produce much more than 90% nitrogen.
2. At relatively low pressures (ie tire pressures) N2, O2 and water vapor will all behave as ideal gases, and follow PV=nRT. Pressure will increase or decrease to the same extent as the temperature increases or decreases regardless of which gas is in the tire. (Even at 300 psi, which is about 20 atm, there is little deviation from ideality.) Therefore the comments about N2 not changing in pressure as the temperature changes are without merit.
3. The rate of effusion (or diffusion) of a gas through a porous membrane depends on the molar mass and to some degree on the molecular diameter. N2 and O2 are almost the same size and N2 is lighter than O2 (28 g/mol vs 32 g/mol) so if either gas were to effuse out of the tire, nitrogen would do it more quickly. Luckily, tires are designed not to be porous membranes.
4. N2 and O2 both have essentially the same specific heat capacity, about 1.0 J/gK, and thermal conductivity, about 0.00026 W/cmK. Water vapor has a specific heat capacity of about 2 J/gK. But remember, water vapor will constitute less than 1% of the air in the tire. So the idea that N2 has different heat handling properties is also without merit.
5. The ozone, O3, in the atmosphere, which is a ground level pollutant, will do a great deal more damage to your tires than the O2 inside the tire. For instance, don't leave a condom out in the air in Los Angeles for a few days. It will develop lots of tiny holes and weaken.
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