P.S.I. highlights importance of auto-inflation at annual tech event
SAN ANTONIO—As it's starting to get freezing across the U.S., now is a good time to talk about one thing that happens to trucks when the temperature drops: tire underinflation. Cold has a habit of making things shrink, like the air molecules in your tires, leading to underinflation.
At best, this means decreased fuel efficiency, increased tire wear, and an overall higher total cost of ownership. At worst, this means a tire blows, which costs money, creates downtime, and can create a safety hazard (road gators) for your driver and others on the road.
But how common is underinflation? According to the North American Council for Freight Efficiency (NACFE), one in five trailers has at least one underinflated trailer tire, and 3% of all trailers operate with four or more tires underinflated by at least 20 psi. Another 3% have at least one less than half-inflated, which is considered flat by CVSA standards and would merit an out-of-service violation.
That 3% might not seem like a lot, but tell a regular civilian driver going home for the holidays that for every 33 tractor-trailers they pass on the highway, one has several tires that could blow at any moment. They would likely find this unacceptable and demand a solution.
Fortunately, that solution has existed for decades in the form of automatic tire inflation systems. These systems attach to the trailer axle and tires, drawing air from a vehicle’s existing air brake system to keep tires at a consistent psi, while prioritizing the air supply to the brake system. This ensures that any issues with the auto-inflate system won’t impact brake performance.
In November, Fleet Maintenance got a chance to get a closer look at one of the leading auto-inflate systems, the Meritor Tire Inflation System (MTIS) from Pressure Systems International. As part of their annual Fleet Technology Event, held in partnership with Cummins-Meritor, P.S.I. provided media with a tour of their MTIS plant in San Antonio.
The MTIS is one of the leading auto-inflate systems available.
“More and more fleets are adopting the technology,” Craig Smith, P.S.I. VP of marketing and communications, told Fleet Maintenance in regard to automatic tire inflation technology in general. “Close to 70% of fleets utilize some sort of automatic tire inflation system, and of those nearly 60% are MTIS.”
Here's how the system works:
What to know
While the benefits to safety and cost benefits are fairly straightforward, maintenance concerns and perceived complexity of the system can be a hurdle for many fleet managers considering implementing the system, Wayne Skinner, Ozark Motor Lines’ VP of fleet maintenance told attendees at the event.
“I didn't want light fixtures to look different, I didn't want wiring, I didn't want air lines, because a technician has to repair any type of issue with the trailer,” he reasoned, listing the concerns he had before the launch of a large retrofitting project. “I want it to be the same. I didn't want the driver's perception to be different.”
Although his data and calculated ROI made the project worth it in the eyes of fleet leaders, he wanted to ensure that his techs and drivers wouldn’t be inconvenienced day-to-day by maintenance complications of the system.
PSI talks MTIS maintenance
Knowing that these concerns can stand in the way of implementing an ATIS, what does upkeep actually entail? After Skinner’s presentation, PSI Fleet Tech attendees were treated to a plant tour and some details about MTIS maintenance that provide insight into how much maintenance an investment into the system would require.
Kellie Taube, VP of global sales for PSI, provided a rundown of the system’s components and their serviceability, explaining that the first priority of the system is to maintain brake performance. Air will go through the regulator and be regulated down to whatever pressure the user has the system set to, and then it travels to the hollow axle on the trailer which it uses as a conduit to get to the rotary union and thru-tee, through air hoses, and into the tire.
Complexity adds costs
But to be clear, not all auto-inflate solutions are created equal, and as the company says, complexity adds costs when it comes to serviceability.
Taube recalled a customer who learned this the hard way. After trying out a different brand of ATIS, they described to her the difficulty of keeping up with the complexity of the system and ended up switching back to the MTIS.
“When you need to change a rotary union on our system, you can unscrew it on the side of the road,” Taube said. “You can pick up that part at any truck stop. It takes all of a couple of minutes, and anybody can do it. You don't have to go into the shop.”
Other components that may need replacement or service are the air hoses, thru-tee, or hubcap. The company reported that the total cost to replace all components of the system is $2.90.
“It's really hard to get mechanics, good ones, and it's really hard to keep them trained,” she relayed. “And when that system was more complex, it was really difficult to keep them up to speed as to what they needed to do to fix it.”
Taube concluded with the estimated TCO, a number the company arrived at based on discussions with a fleet that had over 40,000 trailers equipped with MTIS for over 10 years.
“When we did the math, it ended up being a whole $7.50 per year, per trailer, to maintain the system, and that was parts and labor combined,” she said. “So it’s just a really inexpensive system overall.”
It seems as though the quality control measures in place at the San Antonio plants have done their job, however, as the parts used in the MTIS stand the test of time.
“Our warranty rate is less than .5%,” Smith said. “The warranty is five years, with most components lasting 15 years and longer.”
