Rokbak ADTs Rule the N.C. Mud

Nov. 30, 2022

Charles Donaldson, owner of Donaldson Grading in Denver, North Carolina, oversees a fleet of 14 articulated dump trucks. He owns three Rokbak RA30s and and seven Terex Trucks TA300s.

This article was contributed by Rokbak.

Two of those newly acquired Rokbak RA30s were dispatched to perform clearance duties at a housing project in Belmont, west of Charlotte. The haulers are busy transporting dirt, debris, and vegetation as the land is levelled in readiness for construction of 86 three and four-bedroom properties at the Rivermist site.

Located relatively close to the western bank of the Catawba River, it’s not unusual for the site to be boggy in places, making operating conditions potentially tricky. But that doesn’t apply to the Rokbaks, according to Donaldson.

“They are really strong in wet conditions,” he says. [T]he RA30s have no issues, even on standard tires.” 

With the 31-ton RA30 fully loaded on its 23.5 R25 tires inflated to 59 psi (front) and 67 psi (rear), its ground pressure is remarkably low, respectively producing about 59 and 67 psi each tire’s total contact area. Enhancing the performance of the highly efficient fully automatic (8 speed) transmission, true independent front suspension and permanent all-wheel (6x6) drive, this culminates in class-leading rim-pull in all working conditions, along with reduced wheel spin and minimized driveline wear.

“Our operators love the gearing and diff lock actuation because they’re always in control rather than a computer,” says onsite general superintendent Chris Preston. “In wet conditions, you really need to be able to do this manually. It is such a great design, Rokbak should keep it forever.”

Simplicity is key to this user-friendly feature, which incorporates electable hydraulically actuated multiplate inter-axle and cross-axle differential locks across all three heavy-duty axles. This enables operators themselves to decide whenever 100 percent cross-axle lock-up is required to maintain momentum over the most challenging terrain.

Incorporating drivetrain gear reduction and manual override function, the 8F/4R-gear transmission enables a productivity-enhancing top speed of 34.1 mph. This perfect mix of effective gearing, plus optimized weight distribution and the fuel-efficient Scania DC9 5-cylinder engine producing 370 horsepower and 1,387 lb.-ft. of torque at 1,400 rpm all means the ADTs can move more loads more quickly.

Donaldson drives his ADTs hard: Each Rokbak RA30 at the Rivermist site will typically work for 10 hours a day, six days per week.

“We’ve been delighted with how well the Rokbak haulers have been performing. There’s been zero issues with them; they just work and work,” Donaldson says. “They’re solid machines, with superb, quiet cabs, and they look great as well.”

About the Author

Rod Sutton

I have served as the editorial lead of Construction Equipment magazine and since 2001. 

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