Strong Superdumps help Mundall Trucking bring "the biggest payload in The Valley"

A big payload is critical to your productivity as a dump truck operator, but to John Mundall it’s only part of the equation. To build success you need to get that material out of the bed quickly and cleanly so you can load up again.

Mundall operates Mundall Trucking, a family-run asphalt hauler in the hotly competitive Phoenix, Ariz., market. His seven-axle “Superdump” trucks set the benchmark for asphalt haulers in the valley: they scale 25.7 tons of material—in the morning, full of fuel, with a driver inside.

It’s the biggest net payload in Phoenix, says Mundall, who started using Superdumps in 1995. “The more you can legally load, the more money you can make,” Mundall says. “We not only haul more payload, we do it more efficiently than anyone running a straight dump truck or tractor and transfer trailer.”

A FIXTURE IN THE PAVING INDUSTRY

Rated at 80,000 pounds gross weight, Mundall’s trucks have a 20,000-pound-capacity set-forward steer axle, three 8,000-pound steerable pushers, and 46,000-pound tandem drives. What defines the Superdump is the Strong Arm trailing axle—also called a booster or flying tag. It swings out of the dump bed down to the pavement on two hydraulic arms, a configuration that allows as much as 26 tons of payload.

Arizona is a bridge-formula state: gross weight limits are determined by the length of the vehicle, the number of axles it has, and how they’re spaced. Trailing 11 to 13 feet behind the rear tandem, the Strong Arm axle stretches the outer bridge measurement—the distance between the first and last axles—to 34 feet, the maximum allowed because of Arizona’s 40-foot overall length law.

Built by Strong Industries Inc., of Houston, Texas, the Strong Arm is a load-bearing axle rated as high as 13,000 pounds. It not only bears a portion of the load, it cantilevers weight forward to the steer axle. On many straight dumps, the steer has capacity to spare because it’s so difficult to evenly distribute weight forward.

“Where it used to take 12 or 15 transfer trailers and six or more 10-wheelers to do 2,000 tons in an eight-hour day, we can do that job with 12 Superdumps in four or five hours,” Mundall says. “So a funny thing happened. Instead of getting 2,000 tons ready for us, the plants would get 3,000 or 4,000 tons ready. Everyone benefited from the Superdump.”

‘THE PERFECT BED FOR PAVING’

So Mundall found another way to stay ahead. 

Strong Industries introduced an innovative, lightweight, high-strength steel Superdump bed to maximize the benefits of the Strong Arm trailing axle. It has three distinct characteristics: an elliptical (radius-shaped) floor that gradually becomes wider toward the rear of the bed; an extended floor that eliminates the need for an asphalt apron; and low tare weight.

Most beds are basically the same shape at either end. In transit, asphalt material becomes compressed, and as a result it comes out of the bed in layers. With the Strong bed, the elliptical-shaped floor and sidewalls become wider toward the rear. It’s like pouring from the large end of a funnel. The payload spreads out and loosens up as it flows out of the bed right where the paver needs it: on the belt of the laydown machine.

“The driver doesn’t have to raise the hoist as high to get the load to break, and the asphalt flows more easily, quickly, and consistently into the paving machine,” says Mundall. A more consistent flow makes it easier to keep the paver full, which enables the operator to run the paver faster.

Another benefit is speed. Mundall says the shape of the bed means he can empty a 26-ton load in the same amount of time that a flat-bottom bed requires to dump 15 tons. And with no apron to clean, the driver can be on his way quickly instead of having to contend with a messy and time-consuming job.

“When we designed this dump bed, one of our goals was to not require an apron,” says Brooks Strong, president of Strong Industries and the company’s lead engineer. “The apron can get down into the paving machine and put so much pressure on it that it lifts the wheels off the ground. Extending the floor was a simple, effective solution that pays off in time and operator safety. With our bed, the driver can pull away from the paving machine, flip a switch, close the tailgate, and leave to reload without dribbling material behind him.”

Mundall adds that the construction and materials on the dump body—the lightweight steel and the aluminum tailgate—afford him the extra half-ton that gets his trucks hired.

“Twelve years ago, my dad and I saw the first Superdumps and decided if Strong ever got the kinks worked out, we’d have to sell our 10-wheelers. If we didn’t buy Superdumps we were going out of business,” Mundall says. “Two years later, we bought 10 Superdumps. Now we have 25.

“You can dump into pits, into paving machines, you can spread. The Strong Arm axle and bed make us able to do any kind of work. Now, if you don’t have a Superdump in the state of Arizona, you’re basically not working.”