Anyone running nitrogen in your tires??
08-25-2008, 04:20 PM
#41
Registered User
I see one benefit to using nitrogen in your tires. If you live in a region with high humidity or an area with extreme tempature changes.
If you live in an area where there is no drastic tempature changes (like LA) I wouldnt bother.....
If you live in an area where there is no drastic tempature changes (like LA) I wouldnt bother.....
08-25-2008, 07:55 PM
#42
Contributing Member
AxelIke will probably correct me if I'm wrong (It's nice to have real Xperts on the forum) , but here's my 2 cents. The nitrogen has less to do with the gas molecules & more to do with the lack of water vapor. Water vapor causes greater expansion when the tires get hot than does "dry" gas. If you live in a dry climate, no point in nitrogen. If you live in a humid climate make sure your compressor has a moisture trap (mine does) & you should be O.K.
Paul
Paul
Avoiding water vapor makes sense in the world of air craft because they fly in cold temperatures, and descend fast enough that the water could freeze out, and not thaw and re-vaporize by the time the plane lands, thus causing a dangerous scenario.
In a truck, the expansion difference is negligible. Water vapor or no, the tire will expand when heated and contract when cold the same amount whether there is air or nitrogen. There will be slight differences, but enough to affect your truck's performance? No.
As Wabbit said, you will get much better performance out of your truck if you simply monitor the tire pressure closely.
08-26-2008, 04:47 AM
#43
Registered User
I pasted the straight dope article here:
"Dear Cecil:
I caught a segment on some car show about modding up your car. One of the things they mentioned was the benefit of filling your tires with nitrogen instead of air. Considering I fill my tires with air and don't have much of a problem constantly refilling them, what is the straight dope on nitrogen in car tires? — Dave from Massachusetts
Cecil replies:
Oh, there are plenty of benefits: (1) Cool fluorescent green valve stem caps (assuming your nitrogen vendor has any marketing savvy), which will look sharp with your spinning wheel covers. (2) Bragging rights. OK, you were behind the curve with cell phones, iPods, thong underwear, etc. Nitrogen in tires is relatively new to the mass market. Now's your chance. (3) Reduced fire danger next time you land your space shuttle or commercial aircraft, and tell me you won't sleep better knowing that.
Most tires are filled with compressed air, which when dry consists of about 78 percent nitrogen, 21 percent oxygen, and 1 percent other gases by volume. Water vapor (humidity) can make up as much as 5 percent of the volume of air under worst-case conditions. Filling your tires with nitrogen mainly does two things: it eliminates moisture, and it replaces skinny oxygen molecules with fat nitrogen molecules, reducing the rate at which compressed gas diffuses through porous tire walls. That means, theoretically at least, that a tire filled with nitrogen retains optimal pressure longer, leading to more uniform tire wear and better gas mileage. The commonly quoted figure is that tires inflated to 32 psi get 3 percent better mileage than at 24 psi.
Does nitrogen make any practical difference? You couldn't prove it by me. I found no scientific tests showing that nitrogen-filled tires stayed inflated longer than average under normal conditions. A car-buff buddy was sure it worked but conceded he had only anecdotal evidence that it did.
As for moisture, changes in humidity affect tire performance two ways. First, the density of humid air fluctuates more with temperature than that of dry air, so removing humidity can keep your tire pressure more consistent, especially when the temperature climbs over 100 degrees Fahrenheit. That may be a legitimate concern in Formula One racing, but it's not much of an issue if you're just tooling around town.
Humidity can also be a factor in wheel maintenance — since pure nitrogen doesn't have moisture in it, supposedly your wheels won't rust as quickly, which could lead to improved wheel performance and air sealing. The question is, how big a problem is wheel rust these days? According to a few tire and wheel shops we contacted, not very. Seriously rusted wheels are uncommon in typical steel-wheeled cars, and many high-performance cars have alloy wheels that don't rust at all. One exception is work vehicles such as dump trucks, which are exposed to a much harsher environment.
Another claim I've seen is that since nitrogen is slightly lighter than air, you'll save weight and get better performance. However, we're talking about a weight difference of less than 4 percent of the gas in the tire — in other words, a difference of less than an ounce for most vehicles. A possibly more realistic benefit is that nitrogen is largely inert chemically at low (i.e., normal) temperatures, so it won't attack the rubber in your tires like oxygen does. Oxygen attack is something both the National Highway Traffic Safety Administration and Ford Research have studied, and can be a problem for tires used for a long time or in rough conditions.
More important, nitrogen doesn't support combustion, which is one reason aircraft and the space shuttle use nitrogen in their tires. The wisdom of this precaution was brought home by the crash of Mexicana Airlines flight 940 on March 31, 1986. Shortly after the Boeing 727 took off from Mexico City en route to Puerto Vallarta, an overheated landing-gear brake caused a tire improperly filled with air instead of nitrogen to overheat as well and explode, rupturing fuel and hydraulic lines. The ensuing fire and crash killed 167 passengers and crew. However, unless your driving habits are of the X-treme variety, the chances of your tires catching fire anytime soon are slim.
Overall, filling up with nitrogen won't hurt and may provide some minimal benefit. Is it worth it? If you go to some place like Costco that does it for free with new tires, sure, why not? Elsewhere, though, I've seen prices quoted as high as $10 per tire, which is way more than I'd pay. Rather than shell out for nitrogen, you'd be better off just checking and adjusting your tire pressure regularly, something the NHTSA says less than 60 percent of U.S. motorists actually do."
—CECIL ADAMS
"Dear Cecil:
I caught a segment on some car show about modding up your car. One of the things they mentioned was the benefit of filling your tires with nitrogen instead of air. Considering I fill my tires with air and don't have much of a problem constantly refilling them, what is the straight dope on nitrogen in car tires? — Dave from Massachusetts
Cecil replies:
Oh, there are plenty of benefits: (1) Cool fluorescent green valve stem caps (assuming your nitrogen vendor has any marketing savvy), which will look sharp with your spinning wheel covers. (2) Bragging rights. OK, you were behind the curve with cell phones, iPods, thong underwear, etc. Nitrogen in tires is relatively new to the mass market. Now's your chance. (3) Reduced fire danger next time you land your space shuttle or commercial aircraft, and tell me you won't sleep better knowing that.
Most tires are filled with compressed air, which when dry consists of about 78 percent nitrogen, 21 percent oxygen, and 1 percent other gases by volume. Water vapor (humidity) can make up as much as 5 percent of the volume of air under worst-case conditions. Filling your tires with nitrogen mainly does two things: it eliminates moisture, and it replaces skinny oxygen molecules with fat nitrogen molecules, reducing the rate at which compressed gas diffuses through porous tire walls. That means, theoretically at least, that a tire filled with nitrogen retains optimal pressure longer, leading to more uniform tire wear and better gas mileage. The commonly quoted figure is that tires inflated to 32 psi get 3 percent better mileage than at 24 psi.
Does nitrogen make any practical difference? You couldn't prove it by me. I found no scientific tests showing that nitrogen-filled tires stayed inflated longer than average under normal conditions. A car-buff buddy was sure it worked but conceded he had only anecdotal evidence that it did.
As for moisture, changes in humidity affect tire performance two ways. First, the density of humid air fluctuates more with temperature than that of dry air, so removing humidity can keep your tire pressure more consistent, especially when the temperature climbs over 100 degrees Fahrenheit. That may be a legitimate concern in Formula One racing, but it's not much of an issue if you're just tooling around town.
Humidity can also be a factor in wheel maintenance — since pure nitrogen doesn't have moisture in it, supposedly your wheels won't rust as quickly, which could lead to improved wheel performance and air sealing. The question is, how big a problem is wheel rust these days? According to a few tire and wheel shops we contacted, not very. Seriously rusted wheels are uncommon in typical steel-wheeled cars, and many high-performance cars have alloy wheels that don't rust at all. One exception is work vehicles such as dump trucks, which are exposed to a much harsher environment.
Another claim I've seen is that since nitrogen is slightly lighter than air, you'll save weight and get better performance. However, we're talking about a weight difference of less than 4 percent of the gas in the tire — in other words, a difference of less than an ounce for most vehicles. A possibly more realistic benefit is that nitrogen is largely inert chemically at low (i.e., normal) temperatures, so it won't attack the rubber in your tires like oxygen does. Oxygen attack is something both the National Highway Traffic Safety Administration and Ford Research have studied, and can be a problem for tires used for a long time or in rough conditions.
More important, nitrogen doesn't support combustion, which is one reason aircraft and the space shuttle use nitrogen in their tires. The wisdom of this precaution was brought home by the crash of Mexicana Airlines flight 940 on March 31, 1986. Shortly after the Boeing 727 took off from Mexico City en route to Puerto Vallarta, an overheated landing-gear brake caused a tire improperly filled with air instead of nitrogen to overheat as well and explode, rupturing fuel and hydraulic lines. The ensuing fire and crash killed 167 passengers and crew. However, unless your driving habits are of the X-treme variety, the chances of your tires catching fire anytime soon are slim.
Overall, filling up with nitrogen won't hurt and may provide some minimal benefit. Is it worth it? If you go to some place like Costco that does it for free with new tires, sure, why not? Elsewhere, though, I've seen prices quoted as high as $10 per tire, which is way more than I'd pay. Rather than shell out for nitrogen, you'd be better off just checking and adjusting your tire pressure regularly, something the NHTSA says less than 60 percent of U.S. motorists actually do."
—CECIL ADAMS
08-26-2008, 05:34 AM
#44
all the benefits of nitrogen assume one thing
you are a lazy clown who doesn't bother check tire pressure
so nitrogen allows you to be a lazy slob a bit more 'cuz it leaks out
less
---------
if you keep the tires inflated to where they should be, there
is zero benefit
you are a lazy clown who doesn't bother check tire pressure
so nitrogen allows you to be a lazy slob a bit more 'cuz it leaks out
less
---------
if you keep the tires inflated to where they should be, there
is zero benefit
08-26-2008, 09:10 AM
#45
Registered User
this was a good thread--wish we had more technical discussion like them. I wonder if we can start a section were we talk about the actual sceince behind stuff? This is the stuff i am always looking for.............
08-26-2008, 03:52 PM
#47
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I'm not an expert.
Avoiding water vapor makes sense in the world of air craft because they fly in cold temperatures, and descend fast enough that the water could freeze out, and not thaw and re-vaporize by the time the plane lands, thus causing a dangerous scenario.
In a truck, the expansion difference is negligible. Water vapor or no, the tire will expand when heated and contract when cold the same amount whether there is air or nitrogen. There will be slight differences, but enough to affect your truck's performance? No.
As Wabbit said, you will get much better performance out of your truck if you simply monitor the tire pressure closely.
Avoiding water vapor makes sense in the world of air craft because they fly in cold temperatures, and descend fast enough that the water could freeze out, and not thaw and re-vaporize by the time the plane lands, thus causing a dangerous scenario.
In a truck, the expansion difference is negligible. Water vapor or no, the tire will expand when heated and contract when cold the same amount whether there is air or nitrogen. There will be slight differences, but enough to affect your truck's performance? No.
As Wabbit said, you will get much better performance out of your truck if you simply monitor the tire pressure closely.
.Paul
08-26-2008, 08:24 PM
#48
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A flat tire does NOT have zero psi of air. It has 14.7 psi at sea level. We do not live in a vacuum. Send the flat tire into space on the shuttle and it will have zero. An air pressure gauge accounts for this and actually measures the difference between the inside and the outside of the wheel.
Air is unlikely to corrode anything inside your wheel. I have 3500 psi of air in a steel SCUBA cylinder that is regularly dunked in salt water. It's pretty safe to say you'll be ok with air.
I know my tires aren't round enough to tell air from N2.
Air is unlikely to corrode anything inside your wheel. I have 3500 psi of air in a steel SCUBA cylinder that is regularly dunked in salt water. It's pretty safe to say you'll be ok with air.
I know my tires aren't round enough to tell air from N2.
08-26-2008, 08:45 PM
#49
Contributing Member
A flat tire does NOT have zero psi of air. It has 14.7 psi at sea level. We do not live in a vacuum. Send the flat tire into space on the shuttle and it will have zero. An air pressure gauge accounts for this and actually measures the difference between the inside and the outside of the wheel.
Air is unlikely to corrode anything inside your wheel. I have 3500 psi of air in a steel SCUBA cylinder that is regularly dunked in salt water. It's pretty safe to say you'll be ok with air.
I know my tires aren't round enough to tell air from N2.
Air is unlikely to corrode anything inside your wheel. I have 3500 psi of air in a steel SCUBA cylinder that is regularly dunked in salt water. It's pretty safe to say you'll be ok with air.
I know my tires aren't round enough to tell air from N2.
Uh dude, 0 psi on an air gauge, such as one found in a tire shop, IS atmospheric pressure.
Thus my point that, when filling a tire with nitrogen, starting at 0 psi on the gauge, you have atmospheric pressure in the tire when you start. So, when filling a tire with nitrogen, you have air in the tire as well, and cannot get pure nitrogen in the tire.
Unless, of course, as you say, you start at a vacuum.
08-26-2008, 11:45 PM
#50
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Agreed good thread! Had not heard of filling a tire with anything other than air in the first place. Simply checking the tire pressure once a week or so could be easilly done in less than the time it takes to fill your tank up with gas. I noticed awhile back that for some kind of reason I would never check my tire pressure unless I pulled up to the free air comp. at a local gas station. Made a mental note of that and check it once a week when I fill up now.
08-27-2008, 09:44 AM
#52
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What?
Uh dude, 0 psi on an air gauge, such as one found in a tire shop, IS atmospheric pressure.
Thus my point that, when filling a tire with nitrogen, starting at 0 psi on the gauge, you have atmospheric pressure in the tire when you start. So, when filling a tire with nitrogen, you have air in the tire as well, and cannot get pure nitrogen in the tire.
Unless, of course, as you say, you start at a vacuum.
Uh dude, 0 psi on an air gauge, such as one found in a tire shop, IS atmospheric pressure.
Thus my point that, when filling a tire with nitrogen, starting at 0 psi on the gauge, you have atmospheric pressure in the tire when you start. So, when filling a tire with nitrogen, you have air in the tire as well, and cannot get pure nitrogen in the tire.
Unless, of course, as you say, you start at a vacuum.
It's a farce. Might as well use dried and filtered SCUBA air that has no moisture. An 80cuft tank only costs $5 to fill and then never air down on the trail again.
Last edited by LarsDennert; 08-27-2008 at 09:51 AM.
08-27-2008, 12:23 PM
#53
Contributing Member
Yea that's my point. If you/they start with 1 atm (14.7psi) of air in your tire which has 21% Oxygen and you add 2 atm (30psi) of Nitrogen then you end up with one third or 7% Oxygen compared to a regular wheel filled with still 21%. Either way you have O2 in there.
It's a farce. Might as well use dried and filtered SCUBA air that has no moisture. An 80cuft tank only costs $5 to fill and then never air down on the trail again.
It's a farce. Might as well use dried and filtered SCUBA air that has no moisture. An 80cuft tank only costs $5 to fill and then never air down on the trail again.
In response: yes.
08-27-2008, 12:31 PM
#54
Registered User
That or get a different hose for you SCUBA tank instead of the secondary and take the tank with you. Then use it to reinflate after the trail. I'm looking at this option somewhere down the line. : )
Problem is you have to have a dive certificate or certified friend to get that $5 fill.
Problem is you have to have a dive certificate or certified friend to get that $5 fill.
08-27-2008, 12:56 PM
#56
http://findarticles.com/p/articles/m...7/ai_n24327013
The more articles I read about it the more it seems that the only documented advantage for using N2 is that it does not leak as quickly as air. I still wonder if it's being inert can have any advantage as far as tire life.
Here's what gets me about the way this is marketed: when listing the benefits of using N2 in your tires, "environmental protection" is slapped on the end. Does it prevent cancer too?
It would be interesting to see what, if any, added energy is necessary to produce pressurized nitrogen over pressurized air. If it is a substantial increase in energy, then marketing N2 filled tires as a "green" thing would be questionable.
The more articles I read about it the more it seems that the only documented advantage for using N2 is that it does not leak as quickly as air. I still wonder if it's being inert can have any advantage as far as tire life.
Here's what gets me about the way this is marketed: when listing the benefits of using N2 in your tires, "environmental protection" is slapped on the end. Does it prevent cancer too?
It would be interesting to see what, if any, added energy is necessary to produce pressurized nitrogen over pressurized air. If it is a substantial increase in energy, then marketing N2 filled tires as a "green" thing would be questionable.
08-27-2008, 01:09 PM
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08-27-2008, 01:22 PM
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