Fleet Management News & Business Info | Commercial Carrier Journal
Issue link: http://read.dmtmag.com/i/725427
68 commercial carrier journal | september 2016 EQUIPMENT: TIRE BALANCING such as U-joints going bad. The driver is able to identify other problems when it's not 'driving like a truck.' " Mike Manges, manager of Good- year's commercial and off-highway tire communications, says imbalances also can contribute to suboptimal steer tire performance. All of the truck's rotating parts except for the tire and wheel assemblies are factory-balanced to prevent damage, Forney says. Left unchecked, fleets are not reaping the residual maintenance benefits that balancing can provide. "Balancing wheel assemblies reduces the damage that vibration causes on lights, bearings, U-joints and other suspension parts, resulting in reduced downtime and lower maintenance costs," he says. Bob Jessee, regional account manager for Centramatic, agrees. "When you eliminate controllable vibrations all day every day, all parts that are vulnerable to vibrations – including but not limited to bearings, tie rod ends, ball joints, king- pins, onboard computers and electronics and gauges – will last longer," Jessee says. Balancing myth and reality While balancing a tire and wheel is a com- mon and expected practice for passenger and light truck tires, the process for fleets is not the same for commercial truck tires. Delvin Webb, U.S. customer engineer- ing support manager for Michelin Truck Tires, says the materials and compounds that make up commercial truck tires and the engineering behind their designs have come a long way over the years, as has the use of aluminum wheels, which has changed the dynamic of the tire and wheel assembly. "In most instances, commercial truck tires do not need to be balanced," he says. "With tighter uniformity standards in manufacturing, tires, wheels, hubs and drums do not need routine balancing." While it is customary to check the balance of the tire and wheel assembly if a driver makes a ride complaint, he usu- ally experiences vibrations through the steering column or the seat, often making it difficult to determine where the actual issue originates. "Michelin recommends that before removing the tire and wheel assembly from the vehicle, the radial and lateral runout be checked by a professional technician," Webb says. "Bent wheels, improper mounting or flat-spotting can cause excessive runout. If balance is still required, a simple static balance with bubble balancer or a wall-mounted axle bearing and hub-type gravity balancer should be sufficient." Jessee calls the idea of not balancing commercial truck tires a myth handed down from previous generations when most trucks had Dayton or spoke-style wheels outfitted with bias ply tires. "Back then, it was believed to be a waste of time and resources to balance truck tires," he says. "This is the generation that started the phrase 'It rides like a truck.' By the time the Budd wheel evolved, and then when radial tires for trucks became most common, the myth and the phrase had stuck." Jessee says "visible and controllable forces" that cause premature tire wear include misalignment, worn suspen- sion parts, worn or incorrectly torqued bearings, incorrectly mounted tires and incorrect air pressure. Imbalance, he says, is an "invisible and also controllable force that is consequently ignored by many. "If a fleet owner neutralizes all of the visible forces and ignores the invisible force – imbalance – he will be wearing out his tires prematurely at least 25 percent faster," Jessee says, noting the opposite is also true. "If a fleet owner neutralizes the imbalance and ignores the visible forces, he will also be wearing out his tires prematurely. All the forces, visible and invisible, must be neu- tralized to get maximum life out of tires." Balancing the tire budget The perception of balancing is changing as goals for lower operating costs take center stage, and Forney says more fleets are looking at tire balancing to not only improve tire life but also improve fuel efficiency by up to 2 percent. "To do so, they are finding more time- efficient methods or are spin-balancing despite the time factor," he says. Before Equal Flexx was introduced 25 years ago, spin-balancing with wheel weights was the only option, he says. Weltzbarker says he's already seeing a tire life improvement of about 30 percent from balancing alone. "Before, we were getting about 50,000 to 55,000 miles," he says. "With balancing, we're up to about 80,000 to 85,000." With the increased usage of low- rolling-resistance tires, fleets have seen a Many fleets have saved time by honing balancing efforts on steer tires, where vibration in the steering wheel can wear on drivers.