Good maintenance practices stretch tire, fuel dollars
Feb 1, 2009 12:00 PM
One Simple and immediate way for fleet managers to make the most of their fuel and tire money is to pay greater attention to proper tire maintenance. Tires not only affect rolling resistance, and thus fuel economy, they influence handling, traction, braking, and load-carrying capability.
To get some ideas on how fleets can improve the return on their investment in tires, Refrigerated Transporter's editor-in-chief David A Kolman spoke with Doug Jones, customer engineering support manager of Michelin Americas Truck Tires. Jones has more than 31 years of experience with commercial truck tires.
Q: With air pressure at the heart of proper tire maintenance, why is it more fleets don't have some type of tire inflation program or tire monitoring and alerting system?
A: In the past, many fleet managers didn't realize that proper tire inflation and maintenance made a difference in terms of fuel economy. But when fuel prices skyrocketed a while back, they became more aware of how to get the most out of their vehicles. That means paying greater attention to engines, aerodynamics, highway speeds, and of course, tire maintenance.
Regular pressure maintenance remains critical because under-inflated tires lead to a reduction in grip, an increased risk of hydroplaning, a greater sensitivity to road hazards, a decrease in tire life, and a rise in fuel consumption.
The use of a tire pressure monitoring system properly designed to alert the driver of abnormal pressure loss constitutes an efficient solution to assist in the maintenance of tire pressures.
Q: In addition to checking air pressure, what should drivers be examining with regard to tires and wheels when performing a vehicle walk-around inspection?
A: Checking air pressure is the most important step, and this should be done with an air gauge, not by kicking or thumping a tire. Drivers should also look for any obvious damage tires may have picked up on the road, including metal or other debris. They also should inspect tires for excessive or irregular wear, and have those tires replaced.
Q: How important is it that tires in dual wheel assemblies be accurately matched as far as having the same tire size and air pressure, and similar tread patterns and tread designs?
A: A good rule to remember with mixing tires is: “When in doubt, don't.” Keep tires with similar tread depths together. The same goes for tread patterns.
The guesswork with tire mixing can be eliminated by using single wide-base tires, such as the Michelin X One tire, which replaces a set of duals.
Q: Is it necessary to have valve caps on all tire valve stems?
A: All valve stems should have metal valve caps to prevent air from escaping out of the tire as the valve core is not the ultimate plug for keeping air in the tire. The valve cap also plays an important role. All missing caps should be replaced.
Q: How does vehicle alignment affect tire life?
A: Alignment is very important for tires and can dramatically impact both tire wear and driver control. One of the challenges drivers face is that alignments are typically performed on a static, unloaded vehicle sitting on a level floor, which does not represent real-world conditions.
The Technology & Maintenance Council (TMC) of the American Trucking Associations (ATA) has published the recommended practice for total vehicle alignment on its website. The document is TMC RP 642.
Q: Can you offer any guidelines or recommendations on tire repairing?
A: As a general rule, never repair tires with damage caused by being run flat or underinflated; damages beyond repair limits; broken or deformed bead wires; and ruptures, creases, or detachment of radial ply too great in length. To repair tires with any one of these conditions would result in a tire that would not be safe for further use.
Q: A case could be made that tire maintenance actually begins with the selection of the appropriate tires for a vehicle's intended application. True?
A: The application does make a big difference in how tires perform and can play a big role in how long the tires remain in service. If a fleet handles mostly terminal-to-terminal loads, then standard line-haul tires should serve well if the fleet manager maintains them properly. If trucks are used for around-town deliveries, they should be fitted with regional steer tires and scrub-resistant drive tires.
Q: Wide-base tires offer maintenance and weight savings for certain types of applications. Can you elaborate?
A: Wide-base singles replace dual tires on commercial vehicles in North America with one wide-base single tire effectively turning 18-wheelers into 10-wheelers for fuel savings — up to 10%, and weight savings — 720 pounds per truck.
The weight savings allow vehicles to increase their payload, which in turn means fewer trucks are needed to carry the same amount of freight.
A single long-haul truck, fitted with Michelin X One tires, can save up to 150 gallons of fuel each month, assuming the truck travels 10,000 miles per month.
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