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nitrogen tire inflation mythsA few weeks ago, we busted two myths about nitrogen tire inflation. Today, we are busting two more (there are quite a bit of myths out there). Since the practice of putting nitrogen in your tires is still new, there’s still a lot of possibility of rumor and falsehoods permeating the scene. Which means, some of us out there need to accept the responsibility of disproving those rumors and dispelling those falsehoods. Here are two more myths, busted:

1) TIRES FILLED WITH NITROGEN ARE NOT AFFECTED BY TEMPERATURE

This may seem like the case, since that’s one of the reasons why NASCAR and the airline industry use this practice. After all, since both race cars and airplanes travel at fast speeds, the ability for nitrogen-filled tires to retain those speeds without bursting makes it seem like nitrogen isn’t affected by temperature. However, nitrogen and compressed air respond to changes in ambient temperature in a similar manner, a 1.9% change of pressure for every 10F change in temperature. The difference lies in the water present in conventional compressed air, where dew points (the dew point temperature is the temperature at which the air can no longer hold all of its water vapor, and some of the water vapor must condense into liquid water. The dew point is always lower than, or equal to the air temperature) can be as high as 70F, compared with -40F+ for nitrogen. As temperature increases, liquid water vaporizes to become a gas and its volume expands causing tire pressure to be higher than that of nitrogen, which goes into the tire as a dry gas. So, the presence of water in a tire contributes to wild pressure variations as temperatures changes. The bottom line is that you will still see pressure changes with nitrogen, but the pressure doesn’t fluctuate as much as it does with compressed air.

2. LOOK AT THE PERIODIC TABLE. NITROGEN MOLECULES ARE NOT LARGER THAN OXYGEN MOLECULES

The periodic table is separated based on molecular weight, not molecular size. That being said, diatomic nitrogen (N2) is slightly larger than diatomic oxygen (O2), and this difference allows it to fit through the relatively tight passage ways between polymer chains in the rubber. The difference in size between O2 and N2 is almost infinitesimal, only about 0.3 x 1o raised to the -10 meters, or 0.00000000003 meters. Thus, diatomic oxygen permeates approximately three to four times faster than diatomic nitrogen through a typical rubber, such as what’s used in tires. Just because oxygen is heavier than nitrogen, doesn’t necessarily mean that it’s also larger than nitrogen.

Overall, nitrogen tire inflation is an excellent practice that will make your tires and driving safer and cheaper in the long run. Since this is something that is still new, there’s going to be plenty of people who don’t believe in the benefits and aren’t going to find this worthwhile. However, many have found this practice to be beneficial and to make a difference with their cars and with their wallets.

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Why Nitrogen?

On August 25, 2011, in Nitrogen Tire Inflation, Proper Tire Pressure, by allisonmreilly
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nitrogen tire inflation

Why is nitrogen used for tire inflation, versus air and other gases?

We’ve talked a lot about nitrogen tire inflation. After all, that is what we’re all about. But, we need to answer the question of “Why Nitrogen?” Why use nitrogen and not helium, carbon, or argon? If the point of nitrogen tire inflation is to reduce the amount of oxygen in the tires, then why do we specifically need nitrogen to accomplish that?

Nitrogen molecules have a more difficult time escaping through the microscopic spaces that exist between a tire’s rubber molecules. Nitrogen is a “slow”, inert gas due to its nonreactive nature with many materials. However, oxygen is a “fast” active gas that reacts with many materials. This reaction is a process called “oxidation.”  Additionally, nitrogen is a dry gas that doesn’t support moisture while oxygen combined with hydrogen makes water (H2O). So, even though air is already 78% nitrogen, that 21% of oxygen is enough to do long-term damage to your tires. Again, nitrogen seems like the most natural fit for tire inflation, but is it really the best fit, or the only fit?

Well, nitrogen is a denser gas than oxygen (and helium and carbon), so that explains why it does a better job of maintaining tire pressure than regular air. Consumers can benefit from the more stable pressures, even more so than the fact that your tires are safer with proper tire pressure. The problem is that humidity (aka water) is a horrible thing to have inside a tire. Water, present as a vapor or even as a liquid in a tire, causes more of a pressure change with temperature swings than dry air does. It also promotes corrosion of the steel or aluminum rim.

However, humidity doesn’t get in there through oxygen and the elements. It gets in there through the regular air systems you find at gas stations. Popular Mechanics remarks that some gas stations don’t do a very good job of keeping the humidity out of their air system. If your tires go unchecked, they can accumulate a lot of water, varying the tire pressure even more so than simple temperature changes.
Nitrogen tire inflation provides a good fix for this. Any system that delivers pure nitrogen is also going to deliver dry nitrogen. Filling tires with nitrogen involves filling and purging several times in succession, diluting the concentration of oxygen in the tire. This will also remove any water.

Sure, filling your tires with nitrogen will cost a little money, since you need to have it specially done. We’ve demonstrated in a previous post that the practice is worth the money in the long run. But, why does it have to cost money? Aren’t air and gases free? Well, they are free to acquire, but it does take time and labor to acquire. You simply can’t just put it in a jar. Nitrogen and other gases have to go in special tanks so they can be used appropriately.

Which brings us to the question of why nitrogen for tire inflation over the other gases. As previously stated, it 78% of the air is nitrogen, making it an incredibly abundant gas. The third most abundant gas is argon, which makes up 0.93% of the world’s atmosphere. Can you imagine how much it would cost to fill your tires with argon!?! It would certainly be an exorbitant amount of money, since it would be difficult to acquire and it would take a long time to acquire enough to fill up some tires. Nitrogen is not only the best fit, but it works out nicely due to it’s large quantities and density to be much more affordable than using any other gas.

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nitrogen tire inflation mythsNitrogen tire inflation is still a new concept. Although it has been embraced by entities such as the airline industry and NASCAR for many years, it still has yet to hit mainstream in the consumer market and in industrial fleets. Some folks have never heard of the practice, or may be skeptical that this whole thing is just a gimmick. Some may just be reluctant to pay money for something that can be done for free, despite the costs. Whatever the case may be, here are two myths about nitrogen tire inflation that we here at Nitrofleet99 are ready to bust.

1.) NITROGEN ELIMINATES THE NEED TO REGULARLY CHECK TIRE PRESSURE. This is absolutely untrue. While nitrogen leaks through a tire at a slower rate than oxygen, that doesn’t eliminate the necessity of regular pressure checks. There are numerous issues (valve stem, puncture, rim seal) that can still cause major leaks within a tire and lead to unsafe driving conditions. Nitrogen will maintain pressure longer than tires filled with compressed air, and will make your tires safer to drive on, but we advise against using nitrogen tire inflation as a substitute for regular pressure checks. Besides, there are other tire problems, such as tread wear, that still require that you pay some attention to tire maintenance.

2.) NITROGEN INFLATION IS ONLY INCREASING NITROGEN FROM 78.1% to 93.4%+, THERE IS NO BENEFIT TO SUCH A SMALL INCREASE. This is an argument that a lot of skeptics use, but what makes nitrogen tire inflation beneficial isn’t the nitrogen itself, but the decrease of oxygen and water vapor. Decreasing the percentage of oxygen is a more important factor than increasing the concentration of nitrogen. When filling your tires with nitrogen for the first time, the tires are purged twice, removing the 78.1% “bad” nitrogen (that is laden with water vapor, oil contamination, particulate, etc.) and replacing it with nitrogen that is clean (99.99% of all liquids and solids removed @ 0.01u) and dry (-40F or lower dewpoint). The nitrogen now has the properties of an engineered gas. Water vapor causes pressure fluctuations during normal driving, so removing it is a distinct advantage. The oxygen also damages the insides of your tire over time, so nitrogen tire inflation allows them to last longer.

Overall, nitrogen tire inflation is an excellent practice that will make your tires and driving safer and cheaper in the long run. Since this is something that is still new, there’s going to be plenty of people who don’t believe in the benefits and aren’t going to find this worthwhile. However, many have found this practice to be beneficial and to make a difference with their cars and with their wallets.

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The Clean Cities Coalition

On April 9, 2011, in Fuel Efficiency, Nitrogen Tire Inflation, by allisonmreilly
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clean cities coalitionConsisting of over 100 coalitions, the Clean Cities Coalition is a government-industry partnership designed to advance our country’s economic, environmental, and energy security by supporting local decisions to adopt practices that contribute to the reduction of petroleum consumption. The program’s 8,400-plus local stakeholders that have helped to reduce the use of petroleum, to add more than half a million alternative fuel vehicles on the road, and to encourage the construction of over 3,000 alternative refueling stations.

Since the inception of Clean Cities in 1993 by the Department of Energy, the program has reduced petroleum consumption by nearly three billion gallons! One way stakeholders can continue to contribute to the reduction is to utilize nitrogen in their tire inflation. Instead of spending time and money purchasing and developing new technology, why not just do something different with the old technology? If anything, it’s simply much more economical.

About 54 percent of Americans drive on under-inflated tires. An under-inflated tire can reduce fuel economy by five percent. This can be fixed with nitrogen, which provides a much more stable tire pressure for a much longer period of time. Nitrogen reduces the average rolling resistance of the tire, thereby improving fuel economy. Five percent may not seem like a lot, however, that five percent adds up to increased fuel and maintenance costs for the many company vehicles of which service and fleet managers are in charge. Besides improved fuel economy, here are a few other ways nitrogen can improve your fleet:

  • Improved Safety: Nitrogen enables more stable tire pressure for longer periods of time, thereby reducing the chances for a blowout.
  • Improved Tire Wear: By eliminating the moisture and oxygen through nitrogen tire inflation, the risk of oxidation of tire walls is significantly reduced, creating better wear characteristics.
  • Improved Tire Pressure Monitoring System Performance: By using nitrogen instead of air in your tires, you reduce “false positive” indications from your tire pressure monitoring system, thereby reducing unnecessary service calls.
  • Improved Rim Life: The moisture and oxygen contained in air accelerates rim rust, causing slow leaks in your tires. The dryness of nitrogen eliminates that condensation.

Whether or not you or your city is a part of the Clean Cities Coalition, it’s very easy for transportation industry professionals to contribute toward the cause. To learn more about how to get more nitrogen, and less air, into your tires, check out NitroFleet99.

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