- Focus on basics first, such as seat and mirror adjustments. An artic’s air ride suspension seat requires adjustments depending on the driver’s weight and comfort level. Don’t over inflate the seats, as too much air can make the seat hard and uncomfortable. And, always wear your seat belt.
Adjust the longer, close view mirrors so you can see both sides of the bedrails with the front and rear chassis’ in a straight line. The smaller, wide view mirrors should adjust so either side of the bed takes up half the view. “This is important when operating in reverse because you need a good line of sight for the side opposite your turning direction,” says K.C. Clarendon, product consultant, articulated dump trucks, John Deere.
- This isn’t your pickup truck – so don’t drive it like one. Artics handle just about any terrain and can travel up to around 40 mph, but operators must pay attention to the jobsite environment. Check for obstructions, clearances or bridge capacities and watch for overhead power lines. “Learn the traffic rules of the job; things such as speed limits, left-hand drive and noise limitations all affect the safety of those on the job,” says Ken Emmett, product manager, Terex Construction Americas. It helps, too, if you read your operator’s manual to know the limitations and characteristics of your truck.
Regardless, stay clear of cliffs or slide areas, and avoid operating across a slope. Whenever possible, operate the artic up and down a slope. “Because articulated dump trucks articulate and oscillate, they are more likely to turn over,” explains Ann Schreifels, articulated truck product specialist, Caterpillar. “Don’t take corners too fast, unless it’s a banked curve. Momentum will tend to propel the load forward and that’s when you’ll tip.”
Also try to avoid sharp turns when the truck’s loaded. Try to make wider, more gradual turns. “You’ll have less tire wear and the truck won’t disturb the ground as much,” Schreifels says.
- Since artics employ automatic transmissions, do not shift manually unless necessary. To limit or hold gear shifting, engage the gear hold so the transmission won’t shift above the current gear but will downshift if needed. “This control is useful for maintaining a lower speed on certain haul roads, or to hold a grade descent on steep downhill runs,” Clarendon notes. When engine over speed conditions occur, however, and the truck must do everything possible to prevent damage to its engine, the gear hold will often disengage.
Engaging the gear hold also prevents “gear hunting,” or when the truck’s transmission upshifts and downshifts between two gears. Clarendon says this often happens when a fully loaded truck climbs a slope in, for instance, third gear, and the rpm increases enough to signal an upshift, but suddenly drops to command a downshift, heating up the transmission. Locking in the gear hold prevents cycling so you can pull the whole grade.
- Know when to engage the retarder. Manufacturers have different retarder systems, but each typically operates from the transmission and uses the truck’s weight and speed to slow it down. “Retarder and braking capacities should be considered in downhill loaded hauls,” Emmett says. To brake efficiently using the retarder, always apply it before cresting a bank, going around a turn or going down a steep grade.
“Before you even run a cycle, measure the grades to know what gear and speed you need to be in so the retarder can control this without having to use the service brakes,” says Buddy Goodman, North American manager, market and project support, Volvo Construction Equipment.
Volvo artics include a variable retarder pedal on the cab floor to the left of the steering column. The more an operator depresses the retarder pedal, the more retarder effect the truck receives.
Caterpillar includes a lever on the steering column for its engine brake, which can be set at three different levels for two-, four- or six-cylinder braking. “When the driver takes his or her foot off the pedal, the retarder sets automatically,” Schreifels says.
Moxy Trucks’ articulated trucks, on the other hand, include a retarder switch on the dash. Some machines also feature charts on the front window or in the cab detailing gear and grade specifics, so drivers can determine when to use the retarder.
As a general rule, use the same gear you used to go up a hill as when you go down it, and only use service brakes when you intend to bring the truck to a complete stop or in icy conditions.
- Don’t overuse the differential locks. Blaine Pressley, product specialist, articulated haulers, Volvo, says new operators commonly make the mistake of activating all differential locks, which makes steering hard, adds wear and tear to the driveline and takes more fuel. Some artics require drivers to engage the differential locks before you need them, making sure the truck is not at a high steering angle and no tires are slipping.
Volvo and Caterpillar, however, allow drivers to engage or disengage the truck’s diff locks on the go so no momentum is lost. Differentials should be engaged before wheel spin occurs, but don’t engage the locks unless you’re in slippery or extremely steep conditions. “Only in adverse situations do you need the rear differential locks,” says Kevin O’Donnell, national sales manger, Moxy Trucks of America.
Once the truck is on firm ground or at high speeds be sure to disengage the locks completely.
- Know your truck’s payload capacity and don’t overload the truck. “People often put more on the truck than it can hold,” Schreifels says. “This slows the truck down and wears tires faster, in addition to straining suspension mounts and other components.”
The more overloaded the truck, the more fuel you’ll burn. If loaded properly, you may make more cycles, gain productivity and reduce costs.
To load an artic, do so over the side, and avoid loading material over the cab. “The excavator or machine operator should pull in as tight as possible and look to be almost 90 degrees with the excavator swing position,” Clarendon notes. “The top of your truck’s bed rails should be almost level with the excavator’s bottom track grousers for maximum efficiency.”
With a four-wheel-drive wheel loader, Clarendon says truck operators want to be in a tight ‘V’ between the pile and the loader’s maximum turning effectiveness. It’s important to have enough room to straighten out the loader’s articulation joint before the machine operator raises the bucket to fully load your truck.
Trucks: Drive like a pro
August 31, 2008