Nitrogen Inflation
Evan Lockridge
Contributing Editor
There's a lot of talk these days about alternative fuels – but what about an alternative for filling up your tires? Nitrogen has been used to air up racing and aircraft tires for years, and now trucking may be ready to reap similar rewards.
The biggest of these rewards is that tires filled with nitrogen lose their pressure more slowly that tires filled with compressed air. On the molecular level, nitrogen is a larger particle than plain old air, so it's harder for nitrogen to seep, or "wick," through the tire rubber or out around the bead area.
As a result, tires filled with nitrogen will maintain proper pressure longer – and maintaining proper tire pressure is the key to tires lasting longer, performing better and avoiding a litany of problems. But that's not the only benefit.
"Compressed ambient air is full of oxygen, hydrogen, nitrogen, ozone, dirt and moisture," explains Curtis Decker, national manager of field engineering, commercial division, Continental Tire. "In other words, there's a lot baggage that comes along with that air. Obviously, this is not the best thing to put into your tires." Nitrogen, on the other hand, is inert, meaning it doesn't carry the impurities you find in compressed air. The contaminants that come with compressed air can lead to corrosion of the wheel inside the tire envelope, as well as degradation of the inner liner of the tire, which can shorten casing life. If you're using nitrogen, this isn't a worry
While some advocates of nitrogen inflation cite cooler-running tires as a reason to do away with the air hose, such benefits aren't directly due to using nitrogen, Decker says. "It's not the mechanism of the nitrogen itself, but rather the mechanism of proper inflation. By the simple fact you are using nitrogen, it means you have an improved tire maintenance program."
So you ask, "Why isn't my fleet using nitrogen?" The answer is simple: cost and availability. It takes special equipment to make nitrogen for inflating tires, but several companies have jumped on the bandwagon in recent years. ARI-Hetra, Branick, Ingersoll-Rand and Parker Hannifin are among the companies that have introduced systems to make nitrogen inflation available in any tire shop or truck maintenance facility. Parker Hannifin recently introduced a mobile system for use on a service truck.
"Fleets are finding that by inflating with nitrogen, there are reduced amounts of maintenance, increases in tire life and fewer tire blowouts, all of which means less downtime, better on-time deliveries and better fuel mileage," says Allan Fish, senior marketing product manager for Parker Hannifin.
One of the expressed concerns about using nitrogen is that using regular air to top off a tire could negate any benefits of nitrogen use. Fish says that's not a problem. Several studies done by tire makers and others have found if a tire maintains 93 percent to 95 percent nitrogen, the benefits are still there. In addition, he notes that tires filled with nitrogen stay properly filled longer than those inflated with air. "One could argue these tractors could go tens of thousands of miles before they need to be topped off, which means they will probably be back at the fleet yard by that time," he says.
But before you go out and buy nitrogen-generating equipment, it's important to figure out if such a system will truly pay off in the long run.
"Depending on the size of your fleet, it becomes cost-effective if you can lower that cost per mile of your tires enough to recapture the cost of the nitrogen inflating equipment," Decker says.
Fish suggests evaluating a half dozen trucks with tires filled with nitrogen against six running in the same region with air. Then look at tire wear and fuel economy over a three-, four- and six-month period.
In just a few years, both men predict there will be a better infrastructure when it comes to finding places that offer nitrogen inflation, though it most likely won't be free. Then again, with advantages over compressed air, nitrogen may be worth paying for.
