Rediscovering the Wheeled Excavator's Versatility
We wondered just how effective one of the world's leading excavators was at handling the myriad of performance challenges encountered on today's job site. So we decided to test one out. And to give us a hand, we enlisted the help of seasoned pro, Gene Held.
Gene is proficient on just about any type of construction machine. With more than 30 years in the International Union of Operating Engineers, he's an instructor at Local 150's Apprenticeship and Skill Improvement facility in Plainfield, Ill. So it was to Gene we turned to help us evaluate a brand-new wheeled excavator that Hyundai kindly loaned us for this installment of Hands-On Earthmoving.
Our Hyundai, a model 200W-7, features a front outrigger, rear blade, 1.05-cubic-yard bucket, 7 foot-10 inch digging arm (shorter and longer versions are available) and a pair of 10.00-20 tube-type tires at each corner. Weighing slightly more than 45,000 pounds, the 200W-7 has a Cummins B5.9-C diesel engine rated at 153 net horsepower. Its hydrostatic drive system uses a two-speed, axial-piston hydraulic motor, which drives through a gearbox and propeller shafts to power conventional planetary axles, front and rear.
As Gene puts it through its paces, here's how it holds up.
"In my opinion," said Held, "I think the rough-terrain configuration of the wheeled excavator, like this Hyundai, is better suited to off-road work than an excavator mounted on a truck chassis. I sometimes had my machine up to its wheel hubs in mud, but you could always use the digging mechanism to move the machine over and drive out. But if I were buying a wheeled excavator, I'd want outriggers front and back to get the most potential from it. The blade is okay, but not really that useful."
Held put the 200W-7 to work initially by opening about 30 feet of trench, 4 feet deep, in some reasonably tough material. He had both the outrigger and the blade deployed, but preferred to dig over the blade-end of the machine.
"The blade is closer to the machine than the outrigger box, so you can bring the bucket in farther. Plus, placing the outrigger box behind you gives added counterweight. The blade also digs in and stops the machine from being pulled toward the trench. But, everything considered, I still think you're better off with an outrigger at each end."
At the end of the trenching run, we asked Held for his impressions. He gave the machine high marks for its digging power, saying that it had excellent breakout force in some really tough digging he encountered. We asked, too, about his take on the overall operator's environment.
"The cab layout is excellent - the control levers are well placed and comfortable to use - and the cabin is nicely appointed. Getting on and off the machine is no problem, and the front glass stores easily. The steering-wheel console telescopes and tilts, that's handy, but the steering wheel is still a blind spot into the trench. But, obviously, it has to be there."
Having worked with Held before on excavator evaluations, we knew that he's not a big fan of selectable modes, preferring instead that the machine simply deliver all the power it has and leave the control to him. But in the interest of the evaluation, he gave the Hyundai's multiple-choice monitor a fair try.
The 200W-7 has three work modes, which automatically adjust its hydraulic priorities for given tasks. The "heavy" mode favors boom speed, "general" favors swing speed, and "breaker" sets up the system for a hydraulic hammer.
"I preferred the boom-priority mode when I was trenching," said Held. "The machine does swing a bit faster in the general mode, but it's plenty fast enough in the other. If you swing these machines too fast, you could get off balance, because they're not as stable as a track machine. So far, though, I have no complaints about stability."
The 200W-7 also allows choosing between two power modes - high and standard - which we assume adjust engine speed and pump performance. Held tried both.
"The high-power mode has a slight edge, but I really don't think there's a marked difference in performance between the two," he said, "except that in the standard mode you get a drop in engine speed. Maybe fuel consumption would be somewhat less in the standard mode."
The machine also has a third choice - the user mode - that essentially allows customizing engine and pump settings (which the machine memorizes) to suit a particular operator. Held doubted that most operators would take the time to learn how to make these adjustments.
To complete the trenching exercise, Held backfilled, basically with the bucket, but saved just a bit of work for the blade.
"You're just defeating your purpose if you choose to use that small blade for backfilling, when you have all that power out in front of you. The blade might be good for minor cleanup work, but it's so close to the machine that it's hard to see the cutting edge, and so, it's difficult to control."
Because the 200W-7's operator's manual was a little vague in some areas, Held needed a few minutes to figure out the machine's travel system, but quickly got the hang of it. The "W/T" switch on the forward console, he said, allows selecting a work or travel configuration. In "travel," hydraulic functions are deactivated and the "high-speed" choice on the monitor can be selected. In the work mode, hydraulic functions are activated, but speed is limited.
"It's a good roading machine," said Held. "Steering and braking are excellent, and the high-speed mode lets you get around the site quickly."
Of some initial concern, however, was the latching mechanism adjacent to the service-brake treadle. A close reading of the manual indicated that the operator must be careful to depress both the latch and the treadle during routine braking. Pushing only the treadle to its full stroke, the manual cautioned, would lock the service brake.
"I was a little cautious of the brake at first," said Held, "but then discovered that the hydrostatic drive system basically brings the machine to a smooth stop, and all you need is a light tap of the pedal. You don't come anywhere near pushing it to full stroke. But the operator should be mindful of the situation."
Craning and lift capabilities
For the craning exercise, Held hooked on to a concrete manhole and made a lift over the 200W-7's deployed outrigger. He then extended the radius as he swung over the side. In his opinion, the outrigger and blade provided a stable platform for this maneuver. After a second lift over the end, this time on-rubber, Held traveled forward with the load to simulate a pick-and-carry situation.
"The machine seems to be a respectable lifter, and there's no problem with pick-and-carry, as long as the load is in front of you. I think that whatever you can pick, you can walk ahead with it."
Digging with tires
In a final exercise, Held used the 200W-7 to dig on-rubber. We at first debated whether this was allowed, because the operator's manual did not specifically address this operating situation. But we concluded that on-rubber digging must be allowed, because the front axle's oscillation feature is locked out when either the service brake is fully depressed and latched or the parking brake applied.
Held was impressed with the machine's performance. It dug strongly in this configuration, he said, but he did caution that it's best to slow down when excavating on tires. He was especially impressed that when digging over the side, he could fully extend the 200W-7's boom and digging arm with a full bucket.
"That's a maneuver I couldn't do with the wheeled machine I ran for the contractor. Everything considered, I'd say the Hyundai is a very capable machine."Ready to Compare Excavators Price Quotes?