Fleet managers are well aware of the importance of proper tire inflation to protect tires. Many are earlier adopters of tire pressure monitoring systems (TPMS) and/or automatic tire inflation systems (ATIS or TIS). Choosing the right systems for each application is important part of protecting your investment, but which one to choose? Picking the right systems starts by knowing your choices.
TPMS vs. ATIS
Al Cohn, director of new product and engineering support for Pressure Systems International Inc. (PSI), says, “Tire pressure monitoring systems, monitor the tire pressures, but don’t add air when the tires are low, with tire pressure readings sent to an in-cab display. Some systems have a color indicator located on the tire valve indicating if the tire pressure is oaky. The tire pressure sensors are mounted on the wheel or on the tire valve.”
ATIS is used primarily on the trailers, which historically have the poorest maintained tire pressures. Cohn notes, “Air is automatically added to the tires as the vehicle is running down the highway when the pressure drops below the control box setting,” he says. “Air is ‘borrowed’ from the air tank on every trailer. The same air used for the ABS braking system and routed though the hollow trailer axle, out through the spindle and then through a rotary union. Hoses are connected to the rotary union while the other end of the hose is connected to the tire valve. A warning light, which the driver sees in his side mirror, informs him when the system is activated and air is being added to a low tire. Maintenance should be identified when the warning light is illuminated as this indicates a tire that needs to be repaired at some point.”
Cohn goes on to say that currently internal ATIS systems are not available for tractors because of the difficulty in routing air. Since trailers have a hollow axle, routing the air is not an issue on trailers. ATIS systems can be spec’d on new equipment or retrofitted in under four man-hours.
Chris Steph, ITMS product manager Stemco LP, explains, “TPMS systems allow drivers and technicians a way to monitor and correct tire pressures as they fall below the desired working pressures. There are a lot of TPMS features and they all provide basic monitoring and notification to the drivers and/or the back office teams. STEMCO tire inflation systems (TIS) actively and automatically inflate tires without user intervention and are primarily geared for trailers due to the easy wheel-end access created by the hollow axle tubes.”
There are a variety of TPMS offerings on the market—some of the newer systems offer more value-based options. Steph adds, “There appears to be some work on TIS for tractors, but until a reliable system is released, TIS will continue to be a trailer centric option for fleets.”
“The most obvious different between TPMS Solutions and TIS Solutions is that TPMS units are technology based systems designed to monitor tire performance indicators and measurements and report those readings in-cab and/or remotely to a fleet maintenance manager,” says Vanessa Hargrave, chief operating officer and director of marketing, for PressurePro. “TIS units are mechanically based systems that are designed to fill a tire when it drops below a certain level of pressure. Both are designed with the same end goal of helping fleets maintain optimal tire pressures, resulting in significant savings and substantial safety benefits reaped through extended tire life, improved fuel economy, decreased downtime, reduced maintenance, improved handling and breaking. Essentially, the differentiators are what information is provided by each unit, and how [and to whom, and in what format] that information is delivered to the customer.”
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