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Nitrogen Tire Inflation: A Lot of Hot Air?


Should your store look into nitrogen inflation of your delivery truck tires? Here’s what I’ve discovered about nitrogen-inflated tires and whether you should look into it for your own business.

Nitrogen-inflated tires: Are they the newest “snake oil” on the block? Is there a real benefit for distributors? What about motorists? Your customers and neighbors are probably already — or will be soon — asking you about nitrogen as a tire inflation media. As a parts pro, you may need some information on this subject.

First off, no, nitrogen will not blow up. That was hydrogen in the Hindenburg. Nitrogen is used in tires on the Space Shuttle, every commercial airliner, Tour de France bicycles and most race cars. Nitrogen is not flammable.

We all know the benefits of having proper tire inflation pressure. Properly inflated tires will run cooler and last up to 30 percent longer, and that’s good, especially for those of us running deliveries all day. A vehicle with properly inflated tires will handle and brake as designed. Properly inflated tires have less rolling resistance, thus better fuel mileage.

If you check your delivery truck tires at the same temperature every week and fill them only with true dry, compressed air, you don’t need nitrogen for tire inflation. And by “dry,” I mean using a refrigerated or membrane drier on your compressed air source. For the remainder of us, there’s nitrogen. Nitrogen has two main benefits. First, it leaks much less than compressed air. Second, it’s “dry” and therefore is better for the lifespan of the tire.

In order to get the benefits of nitrogen, there are some basic quality requirements. The inflated tire must have at least a 95 percent concentration of nitrogen. Not 94.5 percent — at least 95 percent. Why is this a problem? Some equipment and procedures are not capable of delivering this needed purity level. Without the needed purity level, you’re not getting the full benefit.

Let’s talk about pressure. The National Highway Traffic Safety Administration (NHTSA) says that the pressure loss from an air-inflated tire may be up to 5 percent per month. That means in the usual three months between vehicle services, there will be a 15 percent drop in inflation pressure. Yes, the owners’ manual in the glove box recommends that pressure checks be performed monthly. Is the average driver following these recommendations? Do your delivery drivers? Probably not.

Bridgestone’s Real Answers newsletter says that nitrogen leaks at approximately 1/6 the rate of compressed air. So, the same tire, filled with 95+ percent nitrogen will lose one psi per month under the same conditions. Note that monthly pressure checks are still required, as per the manufacturer.
Wait a minute, what about the new Tire Pressure Monitoring Systems (TPMS) on newer cars? Do you still need to check air pressure? Yes, because the system only sets a warning light when the tire is 25 percent under or over inflated. A tire 25 percent low will cause wasted fuel and poor handling and may fail because of extreme heat.

This discussion of TPMS leads to the other advantage of nitrogen. Nitrogen is dry; there’s no water vapor or oxygen. The TPMS sensors have small holes that the inflation media must pass through. Any dirt or water may clog or rust the hole, rendering the sensor useless. The water vapor also corrodes the valve core.

Water vapor is the culprit responsible for the large temperature-related pressure changes. A tire inflated with compressed air may contain enough water vapor to condense into liquid at low temperature conditions. This will cause a drop in pressure. The water vapor may also turn into steam at high speeds, causing an over inflation problem. Over time, water vapor also attacks alloy wheels, valve stems and cores and the steel belts in the tire.

What about oxygen? Oxygen is an oxidizer, and is the cause of sidewall “dry rot.” This is the reason Ford recommends that tires be replaced every six years, regardless of tread depth.
OK, what do the car and tire manufacturers say about nitrogen? Well Acura and Honda say ‘no!’ GM puts limits on the recommendation. Why? While both GM and Honda recognize the benefits of quality nitrogen inflation, they have a problem, as they should, with providers that can’t meet the necessary quality criteria. Remember, you need at least 95 percent purity in the inflated tire. Both of these OEMs warn about reduced effects from poor-quality nitrogen providers and/or topping off with regular compressed air.

Michelin, Goodyear and Bridgestone/Firestone recognize that nitrogen leaks less than compressed air. These companies also stress the need for monthly pressure checks.

Finally, nitrogen tire inflation has caused some semi-religious experiences for some users. I have heard of huge mileage increases, ride quality improvement, reduced back shifting out of overdrive while climbing hills, increased stability while hauling heavy loads and on and on. If any of these happen to you, you may use them in your discussions, but use the disclaimer “your results may vary.”

Need another reason? The U.S. Department of Energy says that this country is wasting more than million gallons of gas a day because of incorrectly inflated tires.

Mike Demers owns and operates Son’s Auto Supply, an ASE Blue Seal Certified distributor, in Westmont, NJ.

Sources of Information on Nitrogen:
• 2003/22775ti.html
• Bridgestone Real Answers Volume 8, Issue 3
• The Goodyear Tire & Rubber Company PSB #2004-09
• Michelin North America PM-03-05
• Tech-Tip_0106 Tires + Nitrogen Gas (GM Fleet and Commercial)
• Passenger tires inflated with nitrogen age slower: Part 2 of 2. Author: John M Baldwin, David R. Bauer, Kevin R. Ellwood, Ford Motor Co. September 20, 2004
• EPA 4250-K-93-001 Your Car and the Environment
• Acura Tech Line Summary Article BTS060804

  Previous Comments
avatar   mike getso   star   5/15/2010   9:41 AM and each have dealer locators using your xip code. I know that these two companies also have a patented process n their generators that assures two passes on passenger and light trucks will assuredly get 95% or better purity. Be suspect of a company that uses a nitrogen bottle and/or only does one pass/purge. Some machines have purity analyzers built in but all analyzers have a life span. A shop that uses a hand held that signals a time to replace it, and then does, will also help assure your purity levels.

avatar   Mike Demers   star   2/4/2010   8:10 AM

Thanks for the comments. Most reliable Nitrogen providers are equipped with a guage that can measure Nitrogen percentage. Just clip on the valve stem and read the percentage.If your provider cannot check purity in the tire--keep looking for a quaslity supplier. Remember, there must be a method for purging the existing "air and water vapor" from the tire. Usually the tire must be filled and purged twice to get proper perecntage.

avatar   Nate Lewis   star   1/28/2010   1:39 PM

For you guys looking for a ready source of 95%+ pure nitrogen, any airport will have this on hand as almost every aircraft tire is filled with nearly-pure nitrogen due to it's pressure stability and inability to absorb moisture.

avatar   Scott L.   star   1/28/2010   1:28 PM

Lets raise the Technology of Tires even further! The Tires that Flew on the SR-71 Blackbird were "Spot" made for the aircraft by either Goodyear or B.F Goodrich. The tires had to survive high landing temps as well as the altitude & generated heat the SR-71 created at high altitude! Supposedly the tires were made from "classified" rubber material. If you see the SR-71 on static diplay, there are twin tires forward and six across the rear. According to reports, the guys at Lockheed were more concerned with rear tire blow outs. If one of the rear six blew, the Blackbird still had five good ones to get down the runway on.

avatar   Nate Lewis   star   1/25/2010   2:05 PM

@Alynne: Here's the thing: the air that we're surrounded with is 70%-ish nitrogen anyway (no internet here for me to get the exact amount, that's just off the top of my head). In essence, when you fill your tires with compressed air, you're getting a fairly nitrogen-rich mixture as it is. If you decide down the road that you don't want to continue filling your tires with pure nitrogen and switch back to topping off with compressed air, you'll only be bringing the mixture closer to the 70% that occurs naturally. There's no negative impact on the tire itsself, you just won't be getting the full benefits of a purely nitrogen-inflated tire.

avatar   Alynne West   star   1/11/2010   7:21 PM

what about when I put more in....does it have to be nitrogen all the time? What will happen if a mix happens in the tire?

avatar   Cliff Broussard   star   12/12/2009   8:04 PM

very well explained, but what about after market tires such as 22 inch rims with not much tire or mud griped tires.Is this safe and as efficent?

avatar   Wolfe   star   8/8/2009   1:42 PM

I second what Jose said. There should be a website that lists nearby places that sell nitrogen for tires. As well as what purity is being sold at each location. I would hate to drive 15 miles to the closest store to find they sell 80%-ish

avatar   Jose Rocca   star   7/26/2009   9:49 AM

So far my only problem is finding a place that even has nitrogen.

avatar   Mike Harrison   star   7/6/2009   5:04 PM

WOW, really cleared up an on going argument we have had.Now, how do I know if I am getting 95% purity?

avatar   Gina Destito   star   6/26/2009   3:16 PM

Info to lobby and market on!

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