Nitrogen inflated tires?
12-01-11, 08:42 AM
#1
Pole Position
Thread Starter
Nitrogen inflated tires?
I've been meaning to ask this but didn't want to look like a noob. But here it goes anyways!
What are the pros and cons of nitrogen inflation of tires?
Does it affect handling at all? I know its thought to prolong the life of your tires supposedly but then does it negatively affect other areas?
I had my dealer inflate all 4 of my tires (Michelin PS2's) with nitrogen since they were doing it for free but I dont know if I like it. It feels different, like the ride is even more stiff now or this just be my imagination I dont know.
What are the pros and cons of nitrogen inflation of tires?
Does it affect handling at all? I know its thought to prolong the life of your tires supposedly but then does it negatively affect other areas?
I had my dealer inflate all 4 of my tires (Michelin PS2's) with nitrogen since they were doing it for free but I dont know if I like it. It feels different, like the ride is even more stiff now or this just be my imagination I dont know.
Last edited by pc1990; 12-01-11 at 08:49 AM.
12-01-11, 08:59 AM
#2
Lexus Test Driver
difference in tire pressure is what you're feeling. There is no way someone could accurately judge whether tires are filled with Nitrogen or just regular just by "feeling it"
12-01-11, 09:06 AM
#3
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Here is a good read for you.
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.
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.
12-01-11, 09:06 AM
#4
Pro is that it keeps your pressures pretty constant whether hot or cold... this can be a hassle as some tires heat up quick and can inflate your tire pressure and when you're on the highway, it feels like the car is floating since it's overinflated...
With our high performance tires, they won't last any longer since it just depends on how u drive IMHO...
The dealer filled my tires from delivery without my request... but from my previous car w/o nitrogen, it beats having to monitor tire pressure more often...
With our high performance tires, they won't last any longer since it just depends on how u drive IMHO...
The dealer filled my tires from delivery without my request... but from my previous car w/o nitrogen, it beats having to monitor tire pressure more often...
12-01-11, 09:08 AM
#5
Other than more consistent psi throughout the temp range there aren't much more benefits. If u got it for free great but I would not pay for it.
I doubt u felt any difference, prolly just in Ur head. Not saying Ur crazy, u were just looking for something that's not there
I doubt u felt any difference, prolly just in Ur head. Not saying Ur crazy, u were just looking for something that's not there
12-01-11, 12:58 PM
#6
Pro is that it keeps your pressures pretty constant whether hot or cold... this can be a hassle as some tires heat up quick and can inflate your tire pressure and when you're on the highway, it feels like the car is floating since it's overinflated...
With our high performance tires, they won't last any longer since it just depends on how u drive IMHO...
The dealer filled my tires from delivery without my request... but from my previous car w/o nitrogen, it beats having to monitor tire pressure more often...
With our high performance tires, they won't last any longer since it just depends on how u drive IMHO...
The dealer filled my tires from delivery without my request... but from my previous car w/o nitrogen, it beats having to monitor tire pressure more often...
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12-01-11, 03:41 PM
#8
Tech Info Resource
iTrader: (2)
We use nitrogen in aircraft for its stability, inert properties, and because it has no water vapor. When you're at 30k feet, the entire planet is at -30F, so when you land, the tires and the (gas filled landing) gear can be pretty cold soaked. Nitrogen's stability will make a big difference.
On the race track, if you're serious, you run nitrogen. Again, it's dry, so you'll see much more stable pressures than running compressed air. Dry compressed air isn't bad either, but it's simpler to buy a nitrogen cylinder to fill your tires than it is to assume you've successfully dried your air.
I've never bothered with nitrogen for my street vehicles. There is no ROI even close to worth it even for HPDEs. Again, if you're SERIOUS at the track, you'll run nitrogen. Even many of the base series won't waste their funding on this, the value just isn't there.
12-02-11, 06:19 AM
#9
12-02-11, 10:31 AM
#10
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Yes it is very much gas specific (R isn't a simple constant). But it's unimportant.
We use nitrogen in aircraft for its stability, inert properties, and because it has no water vapor. When you're at 30k feet, the entire planet is at -30F, so when you land, the tires and the (gas filled landing) gear can be pretty cold soaked. Nitrogen's stability will make a big difference.
On the race track, if you're serious, you run nitrogen. Again, it's dry, so you'll see much more stable pressures than running compressed air. Dry compressed air isn't bad either, but it's simpler to buy a nitrogen cylinder to fill your tires than it is to assume you've successfully dried your air.
I've never bothered with nitrogen for my street vehicles. There is no ROI even close to worth it even for HPDEs. Again, if you're SERIOUS at the track, you'll run nitrogen. Even many of the base series won't waste their funding on this, the value just isn't there.
We use nitrogen in aircraft for its stability, inert properties, and because it has no water vapor. When you're at 30k feet, the entire planet is at -30F, so when you land, the tires and the (gas filled landing) gear can be pretty cold soaked. Nitrogen's stability will make a big difference.
On the race track, if you're serious, you run nitrogen. Again, it's dry, so you'll see much more stable pressures than running compressed air. Dry compressed air isn't bad either, but it's simpler to buy a nitrogen cylinder to fill your tires than it is to assume you've successfully dried your air.
I've never bothered with nitrogen for my street vehicles. There is no ROI even close to worth it even for HPDEs. Again, if you're SERIOUS at the track, you'll run nitrogen. Even many of the base series won't waste their funding on this, the value just isn't there.
In racing for example, my buddy works for an ALMS Porsche Team, and when they are filling their tires, they have a special machine for their BBS wheels thats sucks out all air within the tire first to ensure that only pure nitrogen goes into the tire because when the slicks heat up tire pressure increase is minimized and therefore the handling and tire gripping characteristics are maintained.
For street cars, maybe you would have a slightly better MPG only because of the consistency of your tire pressure. But then again MPG is best regulated with your foot.
12-03-11, 08:44 AM
#11
Nitrogen in tires and hokum.
OK, let's get the record straight on this. Air is already 78% nitrogen so the difference in using compressed air vs pure nitrogen is small. Nitrogen is supposed to even tire pressure because it diffuses more slowly through a tire sidewall. The difference in the rate of diffusion between air and pure nitrogen is governed by Graham's Law which states the the ratio of the rates is equal to the square root of the ratio of the molecular weights of the gases. An infinitesimal difference. If there is even a tiny tiny leak in a tire, its effect would be far larger than this diffusion difference. Water vapor obeys the gas law (PV=nRT) just as any other gas. Keeping humidity out of a tire is thus only a concern about corrosion - not much of that goes on during a race. There is an article posted on the internet:
http://www.epicentermotorsports.com/...on_Article.pdf
which explains (with a graph!) that tire pressures are made uneven by water vapor in a tire. This is not true if it is water vapor. If there is any moisture in the tire and it's condensed (i.e. liquid form) on the inside, the vapor pressure of the water will increase logarithmically as the graph shows (Clausius-Clapeyron equation). In other words, IF there is any liquid water inside the tire, the gas pressure of the tire due to the water will increase logarithmically with temperature.
So the air compressor used to fill the tires would have to spray liquid water into the tire to make this scenario important. That is not out of the question, but if the air is filtered in any way, it would not be an issue. Also, the amount of liquid would have to be more than a few drops for a real difference to be made.
Cylinder nitrogen is being presumed as absolutely dry. It may not be. Cylinder nitrogen, or just about any cylinder gas can also have water vapor in it. When inert gases are used in dry boxes where there are compounds that will react with water, the cylinder gas is filtered through drying agents to remove the residual moisture.
In racing - and especially if money is not a concern - no stone is left unturned to save time. Someone thought of the tire nitrogen thing and then there was a lot of rationalization about why it works. If anyone knows of testing results of air vs nitrogen where the variables were vigorously controlled, please post the data. I couldn't find any on the internet.
http://www.epicentermotorsports.com/...on_Article.pdf
which explains (with a graph!) that tire pressures are made uneven by water vapor in a tire. This is not true if it is water vapor. If there is any moisture in the tire and it's condensed (i.e. liquid form) on the inside, the vapor pressure of the water will increase logarithmically as the graph shows (Clausius-Clapeyron equation). In other words, IF there is any liquid water inside the tire, the gas pressure of the tire due to the water will increase logarithmically with temperature.
So the air compressor used to fill the tires would have to spray liquid water into the tire to make this scenario important. That is not out of the question, but if the air is filtered in any way, it would not be an issue. Also, the amount of liquid would have to be more than a few drops for a real difference to be made.
Cylinder nitrogen is being presumed as absolutely dry. It may not be. Cylinder nitrogen, or just about any cylinder gas can also have water vapor in it. When inert gases are used in dry boxes where there are compounds that will react with water, the cylinder gas is filtered through drying agents to remove the residual moisture.
In racing - and especially if money is not a concern - no stone is left unturned to save time. Someone thought of the tire nitrogen thing and then there was a lot of rationalization about why it works. If anyone knows of testing results of air vs nitrogen where the variables were vigorously controlled, please post the data. I couldn't find any on the internet.
12-04-11, 02:41 AM
#12
Lexus Test Driver
Pros? I don't belive there are any real "pros".
Cons? Cost and, if you want to keep your tires nitrogen-filled, you can't get them topped off everywhere or even at home.
All in all, a great marketing strategy designed to part you from your money.
Cons? Cost and, if you want to keep your tires nitrogen-filled, you can't get them topped off everywhere or even at home.
All in all, a great marketing strategy designed to part you from your money.
12-04-11, 06:07 AM
#13
Scam
I will say with 100% certainty that you will notice NO ride difference when using Nitrogen in your tires. Our shop sells right around 70 sets off tires per week, and we have had customers request this, (some people just have to have the latest greatest fad out) and unless the tire has a vacuum pulled on it after it is mounted to ensure there is NO ambient air inside the tire this all becomes a moot point. (Please also remember that water based lubricant is used to install the tires on the wheel, thereby inducing moisture to the process) We have seen NO discernible difference in the tires wear characteristics, or their ability to retain air pressure over their service life since this process has been on the market. Just to show the "infinite wisdom" of our government The state of Pennsylvania was offering to PAY (by the way of a grant) for the equipment necessary to fill tires with nitrogen, due to the "GREAT" environmental impact it would have! What this stinks of is some important people have invested heavily in these nitrogen filling machine companies!
12-04-11, 07:01 AM
#14
Lou
12-05-11, 04:38 PM
#15
Tech Info Resource
iTrader: (2)
OK, let's get the record straight on this. Air is already 78% nitrogen so the difference in using compressed air vs pure nitrogen is small. Nitrogen is supposed to even tire pressure because it diffuses more slowly through a tire sidewall. The difference in the rate of diffusion between air and pure nitrogen is governed by Graham's Law which states the the ratio of the rates is equal to the square root of the ratio of the molecular weights of the gases. An infinitesimal difference. If there is even a tiny tiny leak in a tire, its effect would be far larger than this diffusion difference. Water vapor obeys the gas law (PV=nRT) just as any other gas. Keeping humidity out of a tire is thus only a concern about corrosion - not much of that goes on during a race. There is an article posted on the internet:
http://www.epicentermotorsports.com/...on_Article.pdf
which explains (with a graph!) that tire pressures are made uneven by water vapor in a tire. This is not true if it is water vapor. If there is any moisture in the tire and it's condensed (i.e. liquid form) on the inside, the vapor pressure of the water will increase logarithmically as the graph shows (Clausius-Clapeyron equation). In other words, IF there is any liquid water inside the tire, the gas pressure of the tire due to the water will increase logarithmically with temperature.
So the air compressor used to fill the tires would have to spray liquid water into the tire to make this scenario important. That is not out of the question, but if the air is filtered in any way, it would not be an issue. Also, the amount of liquid would have to be more than a few drops for a real difference to be made.
Cylinder nitrogen is being presumed as absolutely dry. It may not be. Cylinder nitrogen, or just about any cylinder gas can also have water vapor in it. When inert gases are used in dry boxes where there are compounds that will react with water, the cylinder gas is filtered through drying agents to remove the residual moisture.
In racing - and especially if money is not a concern - no stone is left unturned to save time. Someone thought of the tire nitrogen thing and then there was a lot of rationalization about why it works. If anyone knows of testing results of air vs nitrogen where the variables were vigorously controlled, please post the data. I couldn't find any on the internet.
http://www.epicentermotorsports.com/...on_Article.pdf
which explains (with a graph!) that tire pressures are made uneven by water vapor in a tire. This is not true if it is water vapor. If there is any moisture in the tire and it's condensed (i.e. liquid form) on the inside, the vapor pressure of the water will increase logarithmically as the graph shows (Clausius-Clapeyron equation). In other words, IF there is any liquid water inside the tire, the gas pressure of the tire due to the water will increase logarithmically with temperature.
So the air compressor used to fill the tires would have to spray liquid water into the tire to make this scenario important. That is not out of the question, but if the air is filtered in any way, it would not be an issue. Also, the amount of liquid would have to be more than a few drops for a real difference to be made.
Cylinder nitrogen is being presumed as absolutely dry. It may not be. Cylinder nitrogen, or just about any cylinder gas can also have water vapor in it. When inert gases are used in dry boxes where there are compounds that will react with water, the cylinder gas is filtered through drying agents to remove the residual moisture.
In racing - and especially if money is not a concern - no stone is left unturned to save time. Someone thought of the tire nitrogen thing and then there was a lot of rationalization about why it works. If anyone knows of testing results of air vs nitrogen where the variables were vigorously controlled, please post the data. I couldn't find any on the internet.
There's all kinds of compression and dispersion going on when making the local atmosphere into compressed air, so you really have no clue about what's going into the tire. It's possible to refrigerate the air and get the water to drop out or use chemical dryer cartridges but neither of these is very cost effective compared to buying a dry nitrogen cylinder. The contents of the cylinder cost you almost nothing, but the cylinder itself is far from cheap and as stated in the article, a full gas cylinder contains a very dangerous amount of energy. Fortunately all gas bottles contain a safety valve inside the neck below the valve to reduce this risk, but nothing can eliminate it.
Still....there's zero good call for this to be a standard on passenger cars used on the street. People would be far ahead to use regular air and check their tires more often than to adopt the whole nitrogen fashion statement.