Nitrogen Tire Inflation

Million Mile Tires? in 1985? Are You Kidding Me?

While this information isn't new, I think it is well worth highlighting.  It shows the significant benefit of nitrogen inflated tires in the commercial truck market.  And there is no doubt that these benefits carry over to the passenger market on some level. 

In 1985, Lawrence R. Sperberg, of the Probe Forensic and Testing Laboratory, conducted a study on nitrogen filled tires.  The title of this study:  Million Mile Truck Tires - Available Today.  He claimed that using nitrogen tire inflation and retreading, commercial trucks could get 1M miles out of their tires.  The author states: "The exhaustive study concluded when a truck tire is new nitrogen inflation will add from 25% to 30% more miles to the initial wear life in comparison to air inflation, while simultaneously reducing tire failures by one half. When the worn tire is retreaded, nitrogen inflation will increase the resultant tread life by over 50% in comparison to air inflation while continuing to protect the tire from failure by roughly the same ratio of 2 to 1."

The reason nitrogen tire inflation  wasnt implemented in 1985 is cost.  Nitrogen was expensive, fuel and tires were not.  Well that has turned upside down now, and it is the time for nitrogen tire inflation.  Can you imagine the dramatic effects had this been implemented 25 years ago?  Significant decrease in tire scrap, fuel usage, greenhouse gas emissions.  The implications are truly staggering. 

While this information isn't new, I think it is well worth highlighting.  It shows the significant benefit of nitrogen inflated tires in the commercial truck market.  And there is no doubt that these benefits carry over to the passenger market on some level. 

In 1985, Lawrence R. Sperberg, of the Probe Forensic and Testing Laboratory, conducted a study on nitrogen filled tires.  The title of this study:  Million Mile Truck Tires - Available Today.  He claimed that using nitrogen tire inflation and retreading, commercial trucks could get 1M miles out of their tires.  The author states: "The exhaustive study concluded when a truck tire is new nitrogen inflation will add from 25% to 30% more miles to the initial wear life in comparison to air inflation, while simultaneously reducing tire failures by one half. When the worn tire is retreaded, nitrogen inflation will increase the resultant tread life by over 50% in comparison to air inflation while continuing to protect the tire from failure by roughly the same ratio of 2 to 1."

The reason nitrogen tire inflation  wasnt implemented in 1985 is cost.  Nitrogen was expensive, fuel and tires were not.  Well that has turned upside down now, and it is the time for nitrogen tire inflation.  Can you imagine the dramatic effects had this been implemented 25 years ago?  Significant decrease in tire scrap, fuel usage, greenhouse gas emissions.  The implications are truly staggering. 

Walmart Fleet Converts to Nitrogen Filled Tires

You may have noticed that Walmart has had a recent focus on green initiatives and sustainability.  They are 60% of the way to doubling their shipping efficiency by 2015.  What is very interesting is that nitrogen filled tires are a part of this sustainability program.

Elizabeth Fretheim, Director of Strategy and Sustainability for Walmart's Fleet Operations says "We are rolling out a program to do nitrogen filling of tires, that will help with rolling resistance."

Walmart has realized that better pressure retention yields improved fuel efficiency and increased tire life.  I have seen the raw data from the initial tests, and the results are spectactular, up to a 50% tire life improvement.  The savings must be  remarkable for Walmart to make the financial commitment,  and invest in the nitrogen tire inflation technology at their fleet locations throughout North America. 

True Costs of Underinflation

I have posted this information before, but with gas prices soaring, I figure it makes sense to cover this information again. 

I found this article from the California Air Resources Board. 

It contains some very interesting facts about the true costs of underinflation.  Some notes from this article, that are absolutely stunning when you consider the affect on fuel consumption:

• NHTSA found that for every 2.96 psi a car or light truck is underinflated, it loses 1% fuel efficiency.  For a set of 4 tires, that is 0.74 psi/tire.  Not very much, and would probably be difficult to determine with most pressure gauges.  If each tire was underinflated by 2.5 psi, which is nothing abnormal and not enough to make the TPMS alarm to come on, the total for the vehicle would be 10 psi, robbing 3.38% from the vehicles fuel efficiency.
• NHTSA found that the average car and light truck in the USA is riding on a set of 4 tires that is underinflated by 10-11 psi.  That means a 3-4% decrease in fuel economy.
• NHTSA also found that tires lose 1.78% of their tread life for each 1 psi they are underinflated.  So, the average case of 10-11% underinflation yields 17.8% less tire life, according to the article. 

Nitrogen tire inflation is a great way to minimize underinflation.  Nitrogen filled tires maintain their pressure 4-6 times longer than air filled tires, allowing drivers to stay closer to their recommended tire pressures between service interavals.  With the cost of gasoline over $4/gallon in most parts of the country, these wasted dollars can add up to significant losses.  Filling tires with nitrogen is a great way to recoup some of these losses. 

TPMS Alarms and Nitrogen Filled Tires

One of the reasons that nitrogen has become very popular in auto dealerships is that it can solve the issues of false TPMS alarms.  TPMS alarms were mandated on all new vehicles starting in 2008, and are designed to alert the driver when the pressure in the tires varies 25% from the recommended set pressure. 

Nitrogen is a huge advantage with TPMS systems for a couple of reasons.  Nitrogen is very dry, minimizing moisture in the tire and ultimately benefiting the TPMS.  Also, by retaining pressure longer, you will have fewer early AM alarms because of overnight temperature fluctuation.  Dealers want the TPMS to function as intended, and nitrogen ensures that happens. 

Here are some FAQ from Tire Warehouse about the benefits of Nitrogen & TPMS.

Volvo Fills All Spare Tires with Nitrogen

Volvo is an auto manufacturer renowned worldwide for their commitment to safety.  Volvo uses nitrogen to inflate the spare tire on all of their passenger vehicles.  And they have been doing it for years.  Filling the spare tire with nitrogen minimizes pressure loss and assures it is closer to set pressure than its air filled counterpart.  Drivers rarely maintain the tire pressure in their spare tire, so filling it with nitrogen helps to guarantee usability when required. 

If it is safer to fill the spare tire with nitrogen, why not fill the four regular tires as well?  Nissan is already doing it with their GTR, and it is only a matter of time before all new vehicles have it.

Nitrogen Tire Inflation and Temperature Change

With cool fall nights fast approaching here in the Northeast, I thought it would be valuable to post an old submission that covers nitrogen tire inflation and temperature change.  I have heard from numerous readers that they find this post to be very valuable, so here goes.

There is no significant difference in expansion and contraction characteristics of nitrogen compared to air when moisture is absent.  Expansion or contraction of either gas, in relation to temperature change, occurs to a similar extent over the commonly encountered pressure and temperature ranges releveant to the discussion of tire inflation.  There is no practical difference as long as the gases are dry in a fixed volume container such as a tire.

On the other hand, water is usually present in the case of conventional compressed air where dewpoints can be as high as 70F, compared with -50F for nitrogen.  At lower temperatures, water (as a liquid) occupies very little volume.  However, as temperature increases liquid water vaporizes to become a gas and its volume expands.  This causes total tire pressure to be higher than it would be in the case of a dry gas, such as nitrogen.  Thus the presence of water in a tire contributes to wild pressure variations as temperatures change. 

The pressure in nitrogen filled tires will change when the temperature changes, just as it does with compressed air filled tires because nitrogen responds to changes in ambient temperature in a similar manner.  For example, when your vehicle is parked, it will lose 1.9% of its pressure for every 10F change in temperature.  These calculations are based on the ideal gas law.  If a tire is filled to 32 psig at a temperature of 75F, and the outdoor temperature is 35F, the tire pressure will drop to 29 psig.  These fluctuations will occur as the temperature rises and falls, regardless of the inflation gas.  Fortunately, tire manufacturers are readily aware of these parameters and set their cold inflation pressures accordingly. 

So, the bottom line is that you will still see pressure changes with nitrogen.  But they should be more consistent and run cooler than if they were filled with compressed air.

Where Can I Get My Tires Filled With Nitrogen?

You have read about all the benefits of nitrogen tire inflation, and now want to get your tires filled.  Where to go?  The Get Nitrogen Institute provides a valuable Dealership Locator here.  Just type in your zip code and they will show you the closest locations.  Good Luck. 

What is the Correct Purity for Nitrogen Tire Inflation

There is quite a bit of confusion in the marketplace about what exactly is the proper purity level for a nitrogen filled tire.  It seems the market has moved toward 95% in a passenger tire, and we ship our equipment to meet this demand.  But  Get Nitrogen recommends >93.4% nitrogen, and Parker agrees. Why?  Well, its all about partial pressures, i.e. the pressure which the gas would have if it alone occupied the volume. 

We know the atmosphere is composed of 20.9% oxygen and 78.1% nitrogen.  So, at atmospheric pressure of 14.7 psia, the partial pressure of oxygen equates to 3.07 psi (.209 * 14.7).  Now, consider the 32 psig pressure in the tire, and that same 20.9% oxygen.  At 32 psig in the tire, the partial pressure of oxygen now equates to 9.76 psi (.209 * (32 + 14.7)).  This increased pressure inside the tire pushes the oxygen out, and oxygen is more than willing to leave.  But if you lower the oxygen content in the tire to 6.6% (thus increasing nitrogen to 94.4%), the partial pressure of oxygen is now 3.07 psi (.066 * (32+14.7)).  The partial pressure of oxygen inside the tire is balanced with the partial pressure of oxygen in the atmoshpere, and it will remain in the tire longer. 

So what happens when you increase the purity above 93.4% in a 32 psig tire?  Well, believe it or not, oxgen will begin to leak back into the tire over time.  NHTSA said the same at this year's ITEC, as shown on the last slide of this presentation. 

Download ITEC08PAPER18C1

Are Nitrogen Filled Tires a Scam

Unfortunately, Google tends to auto populate Nitrogen Tire Inflation Scam.  I clicked on a few of the links, and was a bit surprised by the wide variety of people that think nitrogen filled tires are a scam.  There is such a misunderstanding that I thought it may be worthwhile to discuss exactly how benefits are derived from nitrogen inflation.

1.  Nitrogen is not a magic gas.  Nitrogen, per se, does not provide the benefit.  Benefits are yielded from the better pressure retention that nitrogen provides.  Better tire pressure provides better gas mileage and longer tire life.  NHTSA has said so in the past (search this blog for NHTSA if you don't believe me).  Not to mention that proper inflation is safer. 

2.  A tire regularly topped off with air will see performance similar to a nitrogen filled tire.  This is true, assuming the air is dry.  That is a big assumption, because the majority of automotive shops do not have a dryer, or one that works properly.  Even those that do have a dryer still leave a significant amount of moisture (vapor) in the compressed air.  Nitrogen is ultra-dry, so it fluctuates less with temperature buildup during driving.  Bridgestone even said so here.  

3. Nitrogen is non-reactive.  The majority of tire rubber breakdown occurs as oxygen permeates through the sidewall of the tire.  A tire filled with nitrogen effectively halts the aging of the tire.  This means your tire retains its strength throughout the life of the tire.   

4. Maximizing your fuel economy and tire life ARE good for the environment.  So, if these can be accomplished with better pressure retention, then nitrogen filled tires are a green offering.

5. As much as we like to pretend we check our tire pressure regularly, the simple fact is that we dont.  The Rubber Manufacturer's Association (Tire Trade Group) has said that 80% of people don't properly check tire pressure.  Nitrogen, while not eliminating that issue, helps to mitigate its damage. 

6. Air is already 79.1% nitrogen, how is increasing it to 93.5% going to make that much of a difference.  It is important to remember that 79.1% nitrogen is laden with water vapor.  During a typical nitrogen inflation service, that "bad" nitrogen is removed, and replaced with clean, dry nitrogen.  No liquid water to cause rusting.  No oil.  No water vapor to condense out and cause pressure fluctuations.  No pipescale or rust to clog your valve stems.  A benefit for your tires. 

Thats it.  A pro-nitrogen tire guy saying that Nitrogen isnt a magic gas?  That nitrogen isnt the end all to proper tire maintenance.  I have always been of the belief that if the benefits are explained properly, people usually don't have a problem understanding the value of nitrogen.

Why Filling a Tire With Nitrogen is Beneficial - An Unbiased Viewpoint

Modern Tire Dealer, a very reputable tire publication, recently ran this article that explains why nitrogen tire inflation is beneficial to the driver.  The research was conducted by Dr. John Daws, prinicipal at Daws Engineering in Phoenix, Arizona.  This summarizes a lot of the information that we have been touting here on our blog.  This is actually powerful information, considering tire dealers have quite a bit to lose (increased sales) through the increased tire life promoted by filling with nitrogen. 

Tire Nitrogen Inflation Testimonial Video for Fleets

In 2005, Parker Hannifin interviewed some nitrogen filled tire users and put together a video testimonial.  Note the benefits that these users have seen, and how truly impressive they are.  While this video focused on commercial truck users, it is important to note that ordinary, everyday drivers should see similar results.  Commercial trucks are steadfast about tire maintenance, and more attentive than the average driver.  They are seeing these benefits even though their tires were maintained regularly with air.

And remember, the user that states he saw a 0.1 mpg improvement is discussing trucks that typically get around 5.5 mpg (a 2% improvement).

You can view the video here:  Nitrogen Tire Inflation Testimonial Video

Rubber News: "Nitrogen's Time Has Come as a Gas Used to Inflate Tires"

Rubber News is a publication that caters to the tire industry (wow,  who knew rubber was such an important component in the tire making process).  There was an article in their January 11th 2010 edition that touts nitrogen as a safety and performance upgrade.  This is one of the best articles I have seen about nitrogen.  It does not overstate the benefits and warns against doing so.  But the article points out that there are tangible benefits, and that the tire makers should be capitalizing on these benefits. 

Jay Leno Nitrogen Tire Video

 Here is a nitrogen tire inflation video from Jay Leno.  It does a pretty good job of explaining the benefits of nitrogen inflation.  He is known for being an avid car enthusiast, and makes sure all of his tires are filled with nitrogen. 

Nitrogen Wand Testimonial Video

Here is a user testimonial video for the new Tiresaver Nitrogen Tire Wand.  This is a great cross section of users, with feedback from an auto dealer, tire dealer, motorcycle dealer and carwash.  Each of these markets is using the wand successfully to retain customers and generate sales.  The nitrogen tire inflation wand is a great entry level product at a small service locale, or augments existing nitrogen service at a busy car dealership.

Fountain Tire Chooses Parker Hannifin Nitrogen Inflation

Fountain Tire has partnered with Parker Hannifin to outfit each of their stores in Canada (well over 100) with Nitrogen tire inflation equipment.  Here is a webpage that explains why Fountain Tire has invested in nitrogen and made it a critical component in their product offering.   

Nitrogen for Tires in 1967?????

Modern Tire Dealer ran a cover story in 1967 about a service station in Houston, TX that was offering nitrogen tire inflation for $1 a tire (wow, 40+ years later, $5 a tire seems like a bargain).  The benefits havent changed over the past 40 years, but what has changed is the affordability of the technology.  This has allowed the proliferation of nitrogen tire inflation services throughout the world.  Here is the July 2009 article from Modern Tire Dealer where they reference the 1967 cover story, and conclude "In summary, the benefits of nitrogen over air in a tire are valid, based on our research." 

A Physicist's View on Nitrogen Tire Inflation

A physicist gives his thoughts on nitrogen for filling tires.  He uses his physics background to explain some of the perceived benefits of nitrogen for tires (vs. compressed air).  I agree with most of his theory, even that there is probably minimal benefit when compared to DRY compressed air and regular top offs.  The problem, however, is that most shops dont even have an air dryer, let alone a major industrial dryer to get down to the extremely low dew point of nitrogen (-58F). 

And $200 seems a bit much for nitrogen tire inflation.  $5-$10 per tire seems to be the industry norm.

Nitrogen an Option for National Tire Safety Week

It is National Tire Safety Week, and this article provides some ideas for safer tires.   One of the options is Nitrogen filled tires, as nitrogen permeates through the tire slower than compressed air.  One of the often forgotten benefits of nitrogen for tires is enhanced safety, as properly inflated tires are much safer than those which are underinflated.  Safety was the primary driver behind TPMS being required on every vehicle, as underinflated tires are more likely to lead to a vehicle accident.  Maintaining the proper tire pressure with nitrogen will provide a safer ride.

Tiresaver Nitrogen Generator for Tire Inflation

Here is a video that shows our Tiresaver Nitrogen Inflation System in action.  This system performs a full vehicle Nitrogen service in less than 10 minutes on cars and about 15 minutes on Light Trucks.  It is designed to provide an in tire nitrogen purity of >95% on all vehicles, via a dual purge & fill cycles. An operator is not required during that time, as the system is completely automatic. 

Next Generation Nitrogen Technology

The April 2011 edition of Modern Tire Dealer has an article about new nitrogen tire filling technology.  The Parker Hannifin nitrogen inflation wand is covered in this article, as well as a number of competing technologies.  What I found most interesting in this article was the fact that 20% of all tire dealers offer nitrogen tire inflation.  This is astonishing market penetration in a relatively short amount of time, considering that it was nearly 0% five years ago.  Nitrogen filled tires are here to stay.