Autocar ACX Heavy Truck Totes a Big Concrete Pump

Driving the Autocar concrete pump

Our subject truck has a Cummins ISX12, an older series product since superseded by the lighter (by about 600 pounds) X12, which will be in a Tri State chassis now on order. Older technology notwithstanding, the ISX12 hasn’t missed a beat. Bought with a 450-horsepower rating, it was locally up-rated to 500 horses with Cummins’ assistance. The extra power helps with propulsion in a truck that weighs 104,000 pounds just sitting still; it travels under permits issued by the states in which Tri State operates—mostly portions of Ohio, West Virginia, and Kentucky. The engine runs through a 6-speed Allison automatic. “With the labor market being what it is, this helps in hiring,” Windland says, because most young people have never driven a manual transmission of any kind, much less the non-synchronized multi-speed gearboxes now in many of Tri State’s trucks.

The Allison made the truck rather easy for me to drive in spite of its mass and bulk. It’s about 48 feet long, 13 feet, 2 inches high, and 102.3 inches wide, so at first it took a little concentration to keep it within the lanes of U.S. 50, which runs east and west through southern Ohio. Along for my demonstration ride was Steve Gilliland, Tri State’s shop foreman, who drove the hefty vehicle out to the highway where I took over. He directed me west about 10 miles to a small truck stop where I turned around and returned to the four-lane U.S. 50, which is a limited-access highway in places, and back toward the company’s headquarters and yard. On the open road, the truck’s ride was something like a motor coach’s, with gentle vertical movements over the twin-steer axles’ suspension and, thanks to air-ride over the tridem rears, virtually shock-free.

At 60 to 65 mph, the tach needle pointed to about 1,700 rpm, where the engine could produce the power and torque needed to climb moderate hills rather easily. The engine brake helped keep speed in check on downgrades. Although fine on the highway, the Autocar could use a deeper low gear to handle stiff hills in West Virginia, Gilliland said. A 7-speed Allison 4700 would probably solve this, but it’s not practical to retrofit this into an existing truck, said Adam Burck, Autocar’s marketing manager.

That’s especially helpful while maneuvering through city streets and onto and out of a job site. Main gauges—speedometer, tachometer, engine-condition, and other information—were directly in front of me, readily visible over the hub of the steering wheel, which tilted and telescoped to suit me and any other driver. The wheel’s diameter was small, at only 18 inches, which added to thigh and belly room. Turning corners required some planning because the wheel must be spun several rotations from center. I found that I had to begin steering early into a turn, and help it return to center after a turn. This is common in trucks with a single 20,000-pound-capacity steer axle, and this Autocar had two of them.

Most controls were readily at hand, with the exception of headlight switches, which were at the center of the cab near the windshield. Autocar put them there so they can be reached from a left- or right-side driver’s position: necessary when this cab sits on a trash-collection chassis with dual operating controls. Gilliland and his co-workers understood that, even though they didn’t like to stretch to reach those switches. They can be mounted further to the left, answered Burck, who was on site to facilitate my visit. Switch placement is among many details that can be specified at ordering time. Autocar’s engineers and line workers commonly deal with many such requests and customization is simply part of what they do.

The ACX’s six-axle chassis has tall frame rails and 10 cross members to stay rigid while traveling on pavement, but flex slightly over uneven ground while carrying the heavy concrete pump body, an Everdigm with a 59-meter-long boom and the capacity to move up to 210 cubic yards an hour. Aside from the strong hydraulic pumping equipment and 5-inch inside-diameter double-wall steel piping that places concrete over long distances, the body includes four massive outriggers that level and stabilize the truck while it works on a job site. Outrigger pads rest on stout cribbing carried in alcoves along the body’s sides so the pads don’t sink into dirt. This South Korea-made Everdigm is the second that Tri State has bought; they are somewhat lower-cost alternatives to the Putzmeister pump bodies that are in other trucks. So far the Everdigms are working well, but Windland said he still favors Putzmeister over all.

And while he’s pleased with the Autocars, he hasn’t ruled out buying more Macks. “It was hard changing the habit of being all Mack,” he said. “We know them, we’re geared toward them with parts, with servicing. But going outside that comfort area was something we had to do.”

Published in Construction Equipment Magazine, July 24, 2019