Don't let something as simple as worn tires put you and your drivers at risk for serious accidents. A pressure monitoring system can make trucks safer and save money.
Most contractors wouldn’t mind increasing their vehicle’s gas mileage, extending the life cycle of expensive tires, improving driving safety and receiving warnings about certain hard-to-access parts that may need repair. They can do just that in their trucks and wheeled equipment with small, innocuous and relatively inexpensive devices called tire pressure monitors.
Since 2008, the federal government has mandated all cars and light trucks be equipped with tire pressure monitoring systems, which utilize small, pressure-activated sensors to transmit both tire pressure and temperature to a dashboard-mounted display panel. And there’s talk that all commercial vehicles may be required to use them sometime in the foreseeable future, says Dan Covington, the chief executive officer of Truck System Technologies Inc., which manufactures the systems.
Tire pressure monitoring systems come in two different configurations for commercial vehicles: external- or internal-mounted sensors. External sensors, which cost about $50 per tire, are about 1 inch tall and 1 inch in diameter, and mount directly on tire valve stems. The internal sensors, which cost about $79 per tire and are about the same size as external sensors, mount on the base of a tire stem inside a tire. The system can monitor up to 34 tires at a time.
How it works
Via a radio frequency, the sensors transmit a tire’s psi and temperature in real time to a small dash display that flush-mounts with a bracket to a dashboard. A military-grade, seven-year-life battery powers the sensors, while the display can be hard-wired into any 12-volt AC outlet. Contractors can also opt for a display powered by a lithium-ion battery that will function on a full charge for seven days (the battery-powered model can attach to a windshield or dashboard via a suction cup). Most companies with larger fleets prefer the hard-wired systems so drivers can’t turn them off, Covington says.
To avoid cross-readings from sensors on other trucks and trailers, each Truck System sensor has a six-digit alphanumeric code programmed into it and etched onto the unit, and that code is scanned into the display. That way, the display only reads and displays information for the tires coded into it. While driving, the display continuously rotates through sensor readings for all the tires, showing data from each tire for about five seconds at a time, and a “map” of the truck or trailer’s undercarriage shows which tire is being monitored, Covington says.
“The external sensors look like a black bottle cap – they don’t leap up at you,” he explains. “The transmitter is located inside the device. The stem is made of brass, which is more durable than aluminum. Some customers prefer external-mounted sensors because they can switch them from trailer to trailer as needed. Others put internal sensors on their trucks and externals on seldom-used trailers.”
The system emits loud beeps when a problem arises, and red LED lights flash on the display for a visual alert. In addition, icons on the display panel tell the operator what’s going wrong, such as a slow leak, a fast leak, over-inflation and high temperature. The audible alarm goes off continuously, but a driver can silence it for 20 minutes before it retrips and starts beeping again.
Underinflated tires can create several problems for contractors. First of all, they can depress gas mileage. To exactly what extent is debatable, but according to the U.S Department of Energy, underinflated tires decrease gas mileage to the tune of more than 1.25 billion gallons of gasoline annually.
“Most truckers would be surprised at how underinflated their tires are,” Covington says. “We randomly sampled 100 trucks at a trucking company and found 30 of them were underinflated from 10 to 30 pounds below the recommended inflation level. And that number seems to hold consistently true industrywide.”
Moreover, air loss occurs naturally; Covington says a typical tire loses 2 to 3 pounds a month. Other factors can also contribute to air loss, ranging from a poor tire bead, external temperature variations, bad valve cores, loose valve stems and puncture from nails and other road debris.
“For commercial trucks, replacing tires is one of the biggest operating expenses,” Covington adds. “And 90 percent of tire-related issues can be addressed before a tire blows, which forces you to buy another tire or make an expensive road-assist call. Properly inflated tires also extend tire life because underinflated tires wear unevenly and create sidewall damage. Ultimately, that wears them out prematurely.”
Worn tires also are prone to dangerous blowouts, which can cause serious accidents that can result in injuries/fatalities and raise insurance rates.
In addition, the sensors can alert drivers to heat being created by a damaged part, such as a bad wheel bearing or a hanging brake caliper. That can save contractors money by revealing a problem before it becomes significantly worse – and more expensive to repair, he says.
“Catastrophic tire failures still can occur without any warning signs,” Covington notes. “But 85 to 90 percent of tire failures exhibit warning signs, like loss of pressure and rising heat. Typically tire temperatures run about 25 percent above the ambient outside temperature.”
In Truck System monitors, a temperature alert is preset at 158 degrees, but operators can change alert parameters on a per-axle basis. “We encourage people to leave it where it is,” he says.
Companies that invest in tire pressure monitoring systems need to educate drivers and mechanics about installation and maintenance procedures, which Covington says are not overly complicated, but do involve time and labor.
“Sometimes when a guy rotates tires, he’ll forget to put the sensors back on or break them without knowing it,” he points out. “But monitoring systems can actually reduce maintenance costs because you don’t have to take time to manually put a gauge on tires every month to check their air pressure. In fact, we have a wand device for fleet applications that you just wave over the sensor – you can even catch trucks and trailers (and check tire pressures) as they’re driving in or off the lot.”