Equipment

[what's new in:] Tire inflation

Oct. 1, 2011

Trailer tires are always going to lose air, whether due to faulty tire stems or simply time. Even tires in good condition can lose up to a pound of air a week. Here's a quick guide to some systems either available or in final research to keep your fleet's tires up and running. According to government and industry-wide research, underinflated tires result in a 2.5 to 3.3% decrease in fuel mileage.

According to government and industry-wide research, underinflated tires result in a 2.5 to 3.3% decrease in fuel mileage. That can mean an added cost of about 12¢/gal. at the pump, according to Goodyear Tire & Rubber Co.

As a result, fleet managers are looking for better fuel economy, fewer roadside service calls, increased tread life, and to reduce time spent manually checking tires. Inside duals are most often overlooked, and pressure gauges may not be accurate even when used correctly, according to Al Cohn, director of new market development & engineering support at Pressure Systems International (PSI).

“The Meritor Tire Inflation System (MTIS) by PSI is a simple design that can be installed [or retrofitted] on virtually any type of trailer,” says Cohn.

CONSTANT AIR

An automatic system with constant air pressure, MTIS uses a patented rotary union that is the only moving part in the system, Cohn points out, significantly reducing maintenance cost. “Air from the existing trailer air supply is routed to a control box, then into each axle. Acting as a conduit, the axles carry air through a rotary union assembly at the spindle end (Thru-T) and then distribute the air to each tire as needed,” Cohn explains.

Excessive wheel-end heat can be monitored by the company's ThermAlert option, which identifies faulty or worn seals and bearing deterioration before they become bigger problems. Cohn says ThermAlert has a special spindle plug that will melt away when wheel-end temperatures reach abnormal levels, allowing air to escape through a vented hubcap and triggering warnings to the driver.

According to Bob Montgomery, vice president of fleet information systems for Stemco, about one-third of all new trailers include an inflation system. “And that number seems to be growing,” he says.

“The technology is still maturing and as such, there is some frustration with many of the systems installed in the marketplace today,” he adds. “These frustrations usually involve maintenance costs, systems that are no longer connected or functioning, and overinflation of tires. Some systems can pressurize or allow contaminants into the wheel end. These are the primary challenges facing inflation manufacturers today, and they are actively working to resolve these issues. At the end of the day, fleets seem to be looking past the costs and frustrations because the value equation is there.”

A TOTAL SOLUTION

The Airgo automatic tire inflation system allows customers to “monitor, maintain and manage their tire needs and expenses,” says Tony Ingram, president of Airgo. “The fleet customers of today have become more cost-conscious, and with the increase in fuel costs, maintenance costs, and costs in general, they are requesting Airgo to provide a system for tire management to prolong tire life, reduce labor costs, improve fuel mileage, and reduce downtime, which in turn would allow them to operate more efficiently and economically.”

Ingram points out that the Airgo system “virtually eliminates any operator involvement” and simplifies both the installation and maintenance process. “Airgo has made the system simple, yet robust to allow for lesser maintenance and more durability. It has basically taken the system one step further to provide the fleet operator peace of mind when it comes to tire management and maintenance,” he says.

While not in production just yet, Goodyear is testing a system that will enable tires to remain inflated at optimum pressure without the need for any external pumps or electronics. All components of the Goodyear Air Maintenance Technology (AMT) are incorporated inside the tire. This includes a miniaturized pump.

“While the technology is complex, the idea behind the AMT system is relatively simple and powered by the tire itself as it rolls down the road,” explains Jean-Claude Kihn, senior vice president & CTO. “A tire that can maintain its own inflation is something drivers have wanted for many years.”

Goodyear is using a $1.5 million grant from the U.S. Dept. of Energy's Office of Vehicle Technology to test the system.