While side-shift backhoes are popular in Europe, North American contractors prefer the fixed boom and wider stabilizer base of a center-mount backhoe-loader.
The wide stabilizer base of a center-mount boom provides consistent lift capacities throughout the range of the swing.
Center-mount backhoe-loaders continue to dominate in the U.S., in part due to fewer space constraints on most construction jobsites.
Because the boom can be offset to the left or right, operators of side-shift backhoe-loaders can dig close to the edge of a structure or a trench with less repositioning of the machine required.
The only real difference between a center-mount backhoe (shown) and a side-shift backhoe is found in the rear frame area.
With a side-shift backhoe, the boom can be tucked up against the rear frame, allowing for ease of transport.
It's important to understand how to properly set up a side-shift backhoe-loader to ensure optimal machine stability.
There’s an interesting dichotomy between the U.S. and Europe when it comes to backhoe-loaders. European contractors have long favored side-shift backhoes, while North American contractors flock to center-mount designs.
Ironically, the differences between the machines are minimal. “Essentially, the tractor is identical from the rear wheel forward and from the back of the boom to the dipper and the bucket,” says Jim Blower, senior product marketing manager, JCB North America. “The only real difference is in the rear frame area.”
As the name implies, the backhoe on a center-mount, or center-pivot, machine is mounted at the center of the rear frame; the stabilizers swing out and down from the sides of the frame. With a side-shift design, the backhoe kingpost is mounted on a carrier that slides from side to side along frame rails; stabilizers mounted on either side of the rails extend vertically.
While the physical differences in the designs may be limited, there is a definite distinction in how they are perceived based on which side of the “pond” you’re on. “Preferences for side-shift and center-pivot backhoe-loaders have historically been geographic,” says Caterpillar’s Kevin Hershberger, “and are driven by a combination of application requirements and regional tradition.”
Excelling in Tight Spaces
Side-shift backhoes have been highly popular in Europe since their introduction in the early ’60s. “Many operators in Europe have always used the side-shift backhoe-loader, and that’s what they’re comfortable with,” says Katie Pullen, brand manager, Case Construction Equipment.
The opposite is true for U.S. operators. “When JCB came to the States in 1970, we came with the side-shift machine because we’d had so much success with it in the rest of the world,” Blower recalls. “It just wasn’t accepted in the market. They liked the center-mount machine — that’s what they had and that’s what they were used to.” JCB subsequently introduced a center-mount design specifically targeted to North American customers.
While steeped in tradition, there are more substantive reasons behind this geographic divide. “Side-shift backhoes are popular in Europe because of the country’s tight working spaces,” says Pullen. “A side-shift backhoe allows an operator to work closer to the edge of buildings compared to a traditional center-mounted backhoe, and it is also good when working in confined areas, which there are many of in Europe.”
“European operators need the extra maneuverability that a side-shift backhoe can provide, with the ability to move the boom to be able to dig right next to a building,” says Louann Hausner, backhoe-loaders and tractor-loaders marketing manager, John Deere Construction & Forestry. “Due to the fact that the boom can be offset to the left or right, operators can dig more precise rectangular excavations and widen trenches with less machine repositioning.” Boom position can also be adjusted to gain maximum visibility into the trench.
Narrow European streets are not conducive to the wider stabilizer base of center-mount machines. Vertical stabilizers, on the other hand, maintain the existing footprint. “The vertical stabilizers raise and lower within the width of the tires, simplifying machine setup along curbs, walls and other obstacles,” says Hausner.
“The vertical stabilizers on the side-shift machine enable it to work in narrower areas, such as against buildings or positioning the machine street side,” adds Hershberger.
Roading is simplified with side shift. According to Pullen, “The sliding swing-frame allows the boom to be tucked in closer to the machine when traveling down the street for a more compact machine envelope.”
This facilitates travel at higher speeds. “The [backhoe] is not hanging off the back causing the machine to bob — to pick the front wheels up and bounce down the road,” Blower explains. “It’s a lot easier to road it with the side-shift design.”
The ability to “tuck in” the boom can be beneficial for loader operation, as well. “When you spin the machine around to load a truck, on a side-shift machine, [the boom] folds up within the width of the machine, so you don’t have to worry about the arm on the back of the machine hitting a wall or a vehicle or whatever else may be around you. It’s all tucked into the back of the machine and out of the way.”
A Matter of Stability
In most cases, U.S. contractors don’t encounter the same space constraints as their international counterparts. “Here in the U.S., it’s quite a bit more open with the streets and the alleyways,” says Andy Capps, product manager, Volvo Construction Equipment.
Consequently, more emphasis is placed on stability than on the footprint of the machine. “In my opinion, stability would be the No. 1 reason the center mount is more desired in the U.S.,” says Capps. “The swing-down, or gullwing, [stabilizers] offer more stability. They give you a wider stance so that when you’re moving material or lifting loads off to the side, the machine is more stable.”
Pullen agrees, noting, “You have better consistency with lift capacities throughout the range of the swing. Plus, you have better ground clearance for stockpiling with the loader.”
The long stabilizer legs on a center-mount machine offer increased side stability, says Hershberger. “This benefit is critical on jobsites with side slopes and when lifting heavy objects or moving them from one side of the machine to the other,” he adds.
Yet, some manufacturers argue the difference in stability is more perception. Blower contends any disparity in stability between configurations is a matter of understanding how to optimally position the machine for the application.
“A lot of people want to keep a center-mount machine because they think it’s more stable,” he states. “It has a wider stabilizer stance when you put the stabilizers down on the ground because of the design of the gullwing legs.” He notes that on JCB’s center-mount machines, there is a 10-ft. 10-in. spread from one stabilizer pad to the other. On the side-shift machines, this distance is 7 ft. 4 in.
However, taken from the midway point of the stabilizer spread, the distance is 5 ft. 5 in. on each side for the center-mount machine and 4 ft. 8 in. for the side shift. “But with a side shift, if you push the carrier all the way to one side of the rear frame, from the center of the boom to the far foot, it is now 6 ft. 7 in., which is wider than that of a center-mount machine. So you have more stability over that one side because you have the whole width of the frame as your stability.”
Another common misnomer, he asserts, concerns leveling on hills. “If you’re working on a hillside, a lot of people think you can set yourself up level on a steeper grade [with a center-mount backhoe],” says Blower. “Where in fact, you can do the same amount of leveling with the vertical stabilizers.”
He says the trick is in the positioning. “The side shift is, in fact, a little more stable if used in the correct way,” he contends. “But it means setting up the machine. With the side-shift machine, you do have to think a bit about what you’re doing. Which side are you going to put the spoil on? Where to have the boom — in the middle or just off to one side — so you get the best stability... There’s just a bit of thought process and adjustment to the machine before you start doing the job.”
Shift in Preference Uncertain
While the vast majority of backhoe-loaders sold in North America have a center-mount design, side-shift models are not entirely relegated to use outside the U.S. “Side-shift backhoes are seen today in U.S. metropolitan areas where busy streets and buildings require construction crews to operate in compact areas,” says Hausner.
Capps sees opportunity for further use in these types of scenarios. “I could see certain contractors doing specialty work where [a side shift] would be very beneficial, especially if you were working in cities where the alleyways are quite tight,” he comments. “It would allow them to be able to dig close to the bank or along the curbing in the narrow alleys, as well as drive it from one location to another vs. having to load a compact excavator on a trailer.”
That said, demand is currently limited. “We do still offer the side-shift machine in North America,” says Blower. “As of late, we’ve sold maybe 15 to 20 a year. It’s not a huge number, but we have a handful of customers who like that style of machine because of the benefits of it when working in tight, confined jobsites. But it’s by no means a growing trend.”
Future growth potential seems limited. “I can definitely see a benefit when working in tight areas. But unlike in Europe, skid steers partnered with a compact excavator are a very popular alternative for these types of applications,” says Pullen. “I think the stability you get from a center-mount machine helps for many utility, road and bridge and construction applications.
“Plus, for rental fleets, customers are more comfortable with and know how to use a center-mounted backhoe,” she continues. “If using a side-shift model, they may have more safety concerns with novice operators not understanding the proper applications for use.”
Due to low market demand, Caterpillar chose to discontinue offering side-shift backhoe-loaders in North America. It continues to evaluate the market, but so far sees no uptick in demand. “Based on our conversations with customers and dealers, it seems unlikely that side-shift backhoes will dominate the U.S. market in the foreseeable future,” says Hershberger. “For the vast majority of U.S. backhoe-loader customers, and the job demands they face, the center-pivot machine has proven to be the preferred machine configuration.”
Still, there is always the potential for this to change. “As construction companies are working globally,” says Hausner, “and getting more exposure to the maneuverability and visibility advantages of these backhoes that are working around the world, we are hearing more requests for side-shift backhoes.”
No clear trend has yet to emerge, but you can bet manufacturers will continue to keep watch. “If the market changes, and our customers and dealers tell us a side shift is preferred here, Cat will certainly deliver,” says Hershberger. ET