Proper Pressure Saves $
But if you're ready to evolve beyond the thump and kick routine, you might be puzzling over what type of inflation system is right for your operation.
Mark Putz
Associate Editor
In a perfect world, your drivers would diligently check tire pressure daily. And these daily rounds would be augmented by a proper weekly stick of each tire with a gauge. But time is money — especially with the new 14-hour day. So many are slipping back into the bad habits of kicking, thumping, or merely eyeballing the inside tires. But you can't afford the high cost of low tire pressure.
Varun Rao, product manager of trailer systems for Arvin Meritor, succinctly observes that trucks without some sort of inflation system lack even an auto-style idiot light. He writes, "Tires are the most numerous item on a vehicle, yet receive the least amount of attention. There are no in-board gauges to inform the driver of their status. Tires costs escalate when one considers the perils posed by underinflation. As has been reported in various publications, trailer tires that are underinflated by as little as 10%, lose 16% of their usable life. If the tires are underinflated by 30%, they return less than half of their usable life. And that's only the cost of replacing the tire. That's still not taking into account the service cost associated with replacing the tire, the loss of revenue while the trailer is being serviced."
But if you're ready to evolve beyond the thump and kick routine, you might be puzzling over what type of system is right for your operation. There are too many systems on the market to mention here, so below we've highlighted some veteran systems and some new kids on the block.
Meritor Tire Inflation Systems (MTIS) by P.S.I is an example of a fully automatic inflation system. It is currently in use by more than 1,000 fleets. In this system, air from the existing trailer air supply is routed to a control box, then into each axle. The axles act as a conduit and carries air through a rotary union assembly at the spindle end, which then distributes the air to each tire as needed.
The Airgo system likewise takes air from the same compressor that supplies the brakes and other on-board components. It supplies air to each tire. All hubcap components are sealed to eliminate water or debris from entering the hub area. The system's removable expansion plug for sealing the axle installs in less than two hours, does not require specialized tools, and is easily removed for periodic cleaning of the axle. The company says the system has been successfully used in all applications, i.e. tanker, van or reefer.
PressurePro from Doran Manufacturing uses tiny transmitters on the valve stems to indicate pressure in each of a truck's tires. The signal is transmitted to a display unit that mounts to the dash and shows wheel position and a digital read-out of the tire pressure when it drifts away from the set pressure. This allows the driver to "see" a leaking tire and stop to add air.
It is comparatively inexpensive and has the potential to eliminate tire loss — the system pays back in less than eight months in fleets with annual mileages of 100,000 miles per unit, according to Doran.
Other systems automatically maintain tire pressure from the trailer's air system. PressureGuard Tire Inflation Systems from Reineke, releases compressed air from the tractor's system when tire pressure drops below the preset pressure level. One concern with any automated inflation system is maintenance on the road. If a tire catches a screw in West Texas, you want the service people to be able to properly reinstall the system. The system also touts quick disconnects at the valve stems. Hoses can be disconnected at the valve stem or at the cap when wheel end work is necessary, and Reineke says it handles any information gaps with decals above each wheel well.
During routine wheel end work and tire changes, valve stem quick disconnects eliminate the time-consuming dismantling of the tire inflation system and the patented aluminum hubcap with integrated air channels and protective ribs prevent valuable components from being damaged.
PressureGuard's easy-to-install design is compatible with virtually all new and existing trailers. And because the system is completely contained on the trailer itself, PressureGuard-equipped trailers can be used with any truck or tractor.
The Tire Mate 2000 features a small wireless transmitter attached to each valve stem. If inflation pressure falls below the trigger pressure, a signal is sent by wireless transmission to a display module in the cab. The driver is alerted by an audible alarm, while a flashing light displays which tire is losing pressure. Each tire is assigned its own pressure transducer (sensor) with a signal code that identifies each tire to the display module.
SmarTire offers a system with a transmitter that snaps into a flexible cradle design. The company says its Interrogator Wand activates the transmitter and eases receiver programming. SmarTire has signed a co-development and marketing agreement and a supply agreement with Haldex Brake Products.
Dual Dynamics offers Crossfire, a dual-tire pressure equalization system. The company says the product also has a feature that automatically isolates the good tire in the event of a failure. When a blowout occurs, the internal safety valve closes immediately with only a slight loss of pressure to the good tire.
And Dana Corp.'s Tire Maintenance System utilizes an electronic control unit (ECU) to ensure robust, yet simple operation. Actual tire pressure is measured with the vehicle operator being notified only if the pressure is below a pre-determined level. Dana TMS also features a non-pressurized design, which helps ensure seal life longevity since the seals are not pressurized when no inflation is required.
Design features include the elimination of any requirements for venting at the wheel to help ensure that hubs remain unpressurized in the event of an air seal leak or line leak. And the system has the ability to record and retrieve low tire events from the ECU.
All of these systems tout a return on the initial investment. And the numbers look good when you consider the improved fuel economy, reduced down-time and an increased return on the investment in your tires.
