Issue link: https://read.dmtmag.com/i/696201
MAINTENANCE MATTERS 22 // OWNER OPERATOR // JULY 2016 retread capabilities. The way a truck is driven "can have a significant effect on the casings – this cannon be understated," Crehan says. These driving habits include curb impacts, braking, emergency stops, speed, route choice, road maneuvers and obstacle avoidance, he says. "The main reason a tire casing is rejected during the retread process is due to the tire being underinflated or overloaded at some point during its lifecycle," says Terry Smouter, business development manager for Continental CVT. Ben Rosenblum, director of Bandag marketing for Bridgestone Commercial, says the company's studies have shown that high- quality casings retread just as well on the second and third retread as they do on the first. "Casings today are built to last many years and multiple retread cycles," he says. "If you maintain the appropriate pressure – and hopefully avoid too many curbs – you'll get the most out of your casings." Trailer owners have more potential for retreading because of options for repositioning tires. A common practice, Rosenblum says, is to buy new steer tires, place the first retread on the drive and the second on the trailer. However, "A steer is not normally retreaded," Crehan says. "An exception would be an all-position tread that could be used on steer axles for specialized low-speed start-and-stop applications like waste haulers and other local delivery." Casings that are rated higher – with fewer repairs and lower heat history – tend to be placed on the drive axle since the torque on those tires leads to higher heat generation, Carnegie says. "As the tire experiences longer heat history or has more repairs needed, then generally it is moved into a less severe axle like the trailer," he says. "But this is not only dependent on the number of times that the tire is retreaded. A tire after its first life could have experienced service conditions and other external conditions that could lead to it being placed on the trailer axle." Likewise, a casing could still be without repairs and in a condition that would allow it to be used on the drive axle, he says. Don't overlook this wear point One aspect of extending tire life often goes undetected until the damage is done. That's a worn wheel end, which causes the wheel to shimmy. Even a slight irregularity there can strip tire tread. The problem is often disguised as something more familiar. "Irregular wear is sometimes misdiagnosed as an alignment issue," says Rick Martin, Meritor's senior aftermarket training manager. "If they see tire wear on a trailer axle or steer axle, they'll usually just take it and have it aligned." No amount of alignment is going to fix a problem caused by a worn wheel end, he says. "You're going to end up with some feathering," says Jim LeClaire, national original equipment sales manager for Webb Wheel Products. "The tire is going to end up squirming." OO Improper inflation and poor rotation are the two primary causes of irregular tire wear.