Manager: Lauren Jongetjes
Title: Fleet tire manager
Fleet: Superior Ready Mix Concrete
Operation: California construction hauler with 700 power units
Wide base tires can be a boon to bulk hauling fleets looking to save on tare weight in order to increase profitable payload capacity while boosting fuel economy. That's especially true for fleets in the construction trade, where a few hundred pounds of extra payload can help clear a worksite of rock debris that much faster.
California-based Superior Ready Mix Concrete has used wide-base tires on its bottom-dump trailers for more than a decade for precisely those reasons, yet it also found a major design flaw in them as well: susceptibility to “stone drilling.”
“In the past, almost every tire on our bottom-dump trailer tires eventually had to be scrapped,” said Lauren Jongetjes, fleet tire manager. “Over time, stones picked up from a job site can drill into the tire's casing, causing damage serious enough to warrant removal from service and in some cases even preventing the tire from being retreaded.”
Losing tire retread capability is no laughing matter either, as a retread represents about a third of the cost of buying a new tire. Thus, each tire and casing irreparably damaged by stones represents a loss of hundreds of dollars in premature replacement, Jongetjes explained.
The Superior Ready Mix fleet includes about 700 power units, with 90 dump trucks, 30 cement powder haulers, 450 concrete mixers, 110 bottom-dump trucks and trailers, plus other additional vehicles in operation across California. Losing tires to stone drilling represented a major chunk of change to its bottom line, so the company started searching for wide-base designs that were resistant to stone damage, without sacrificing any of the performance benefits they'd come to expect with these models.
Last year, Superior started testing Continental Tire North America's HTL1 wide base tire, designed specifically to handle on/off road and construction trucking applications. The HTL1 features 13/32-in. tread depth to minimize irregular wear and maximize fuel efficiency. A six-rib design evenly distributes the trailer's load over the crown of the tire to protect the tread pattern from irregular wear, with a decoupler rib providing better irregular wear resistance at the tire's shoulder.
More importantly, the HTL1 comes equipped with special “pyramidal” grooves to help eject stones that get trapped in the tire tread, explained Roger Stansbie, Continental's director of radial truck tire technologies.
“These pyramidal stone grooves work by ejecting these small stones or preventing them from reaching the bottom of the groove, where premature casing damage can start,” Stansbie said. “Even with the addition of the pyramids, the groove bottom still offers sufficient passage for water, ice and snow.”
Stansbie noted that another advantage of this design is that the pyramid grooves can withstand abuse and wear to a greater degree because they are connected to the groove side as opposed to free-standing. This turned out to be the best solution for Superior. Maximum load capacity of each HTL1 is 10,200 lbs. at 120 psi, and the tires can be used at a maximum sustained speed of 75 mph.
There's another benefit, too, Jongetjes noted. As California freeways are often crowded, Superior often had to pay a significant amount each month in broken windshield claims from passing motorists. But since the HTL1 reduces the initial trapping of the stones in the first place, Jongetjes expects to significantly reduce the costs associated with windshield replacement claims.
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