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Urban Myth or What?



Potter continued to assert that as such, astute distributors are paying closer attention tire maintenance. He went on to say that some fleets are currently experimenting with replacing the air in their tires with nitrogen to allow them to run cooler and retain desired pressures longer.

As if on cue, the next panelist, John Tracy, president, Dot Foods, Mount Sterling, IL, shared the fact that his company is looking into the use of nitrogen rather than air to inflate their tires.

Following the panel discussion and our series of fuel cost articles, questions regarding the validity of this practice were presented to ID Access and we got to work.

If nitrogen-inflated tires had cost-savings potential certainly the American Trucking Association, Alexandria, VA, would be able to provide studies of how they were being employed. When asked, its representative noted:

ONE EXPERT'S OPINION "It is true that some fleets are using nitrogen to inflate tires. Nitrogen is commonly used in racecar tires because there is less pressure buildup as the tires run. The Federal Aviation Administration requires nitrogen be used in aircraft tires on "braked wheels" because excessive brake heat can cause an explosion.

"The use of nitrogen is also an affordable way to inflate tires with a gas that is not prone to moisture contamination - as is the case with oxygen - which eliminates the problems of tires rusting from the inside out.

"Another popular benefit of nitrogen is that it permeates a tire liner three to four times slower than oxygen and runs 15-20% cooler than normal air inflation which results in increased tire life an extended tread wear."

That sounds promising. However, the ATA's response hinted at the fact that there may be no research readily available concerning over-the-road fleet use of nitrogen as a replacement for air. However, their response was encouraging because it highlighted this practice was being employed and perhaps has applicability for foodservice distributors. So, we looked into this further.

Air-inflated tires contain 78% nitrogen and 21% oxygen. Proponents of nitrogen-inflated tires state that nitrogen should be kept at 95% to receive its maximum benefit. By definition nitrogen is a dry, inert gas whose main benefit is its molecular structure; nitrogen molecules are considerably larger than oxygen molecules, which accounts for why these molecules do not permeate a tire nearly as quickly as oxygen.

An article published in July 2004 edition of Tire Review presents a detailed discussion concerning this practice. The article reveals this discussion has been going on for 40 years and interesting to our efforts, the author notes "given the soaring price of fuel (2004) and safety concerns, nitrogen inflation had become the hot topic in the tire industry." Cutting to the chase, the excerpts in the article cite several exciting claims regarding fuel efficiency, extended tire life and other benefits. But note - "the real problem appears to be sorting through the science and the hype."

With this in mind, the research continued with the focus centered on something more specific to try to quantify benefits for foodservice distributors -under inflated tires.

In his NRA seminar presentation Steve Potter also pointed out that experience has shown that five pounds of low air pressure equals one extra gallon of fuel consumed every 100 miles driven.

Given this statement, the pertinent question is - will the use of nitrogen as opposed to air make a difference to the maintenance of correct air pressure? In a word - yes.

NITROGEN REQUIRES 95% INFLATION CAPACITY Kevin Rohlwing, senior vice president of education and technical services; Tire Industry Association, Bowie, MD, explained, "Nitrogen does have a positive impact because it "bleeds" out of the tire at a slower rate. A tire inflated with standard air will lose about 1-2 psi per month. If the same tire is inflated with pure nitrogen, the rate of loss will be less. Proper inflation pressure leads to better tread wear and fewer heat-related failures."

The Bridgestone/Firestone Commercial Truck Tires website concurs noting: While both nitrogen and oxygen can permeate rubber, nitrogen does it much more slowly. It might take six months to lose 2 psi with nitrogen, compared to just a month with air.

Further validation came from a discussion posted on the Australian Tyre Manufacturers Association website. The comments note that nitrogen-inflated tires retain their pressure longer and warn "nitrogen is not a set and forget option... even if there's nothing 'wrong,' you can still be losing pressure" Hence, the principles of good fleet management requiring vigilance do not go away with the use of nitrogen.

In fact, the use of nitrogen adds a second step to ensuring that the correct pressure is maintained. One must make sure that the tire is inflated with the right amount of nitrogen, 95%, to obtain its full benefit. This check can be done by using a hand-held nitrogen analyzer. Plus, the anecdotal evidence highlights this task can be done less often.

Typically, with air-inflated tires, a cold inflation pressure check should be performed at least once a month, and preferably once a week. According to those with experience using nitrogen-inflated tires, this task can be performed every three months. Plus, general experience indicates that these tires do not require additional nitrogen for six to nine months. Therefore, there is a manpower cost-savings to be considered.

CAN NITROGEN REDUCE COSTS? It appears that nitrogen does maintain consistent pressure better then air and therefore can decrease fuel consumption if properly maintained. So if this is the case, the follow-up question n is - is nitrogen use a good tactic to reduce cost?

Rohlwing notes that one could invest in a nitrogen inflation generator for a few thousand dollars to more than $10,000. Rohlwing continues his train of thought adding that the maximum benefit is accrued to the company that does its entire tire work in-house. He goes on to say if the company's tire work is outsourced then very few commercial tire dealers will be able to provide this service.

Our conversations and web-based searches with companies that sell nitrogen generators present a broader dollar range than Rohlwing. Their estimates are based on the size of the generator and the number of tires to be inflated. For additional information on generators, their cost and requirements, companies to contact include: Branick Industries (www.branick.com), NitroFill (www.pneumatech.com), Parker Hannifin Corp. (www.parker.com) and Rema Tip Top (www.rematiptop.com).

Did we conclude that the use of nitrogen-inflated tires as a means of reducing fuel consumption was an urban myth? No, for some companies it might be a viable solution. But- nowhere did we find scientific data that pin pointed potential dollar savings in the use of nitrogen over air.

The conclusions drawn from our conversations and research are:
  • There are benefits to using nitrogen in obtaining better tire pressure retention, fuel-cost savings, extending tire life (26%), and tire blow-out reduction.
  • In lieu of any research studies, each company has to do the math for themselves.
  • Good questions to ask when assessing a generator company include -are there warrantees? Does your generator require membrane (or filter) that must be replaced on a regular basis? (some do and some do not) Will they back-up their claims?

    Only time will tell, but we believe we'll be reporting more on this subject. Nitrogen is an interesting option.

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