The newest generation of big skid steer loaders is capable of shaking off its utility-machine mantle and competing aggressively for production tasks with electronic-over-hydraulic joysticks and steadily more-refined cockpits. Most sophisticated features are optional, though, and buyers looking to save money on big loaders can still get simpler machines for utility work.
Options may come into play when outfitting large-frame loaders for production. But fundamentals such as the distribution of weight between front axle and rear and the choice of radial- or vertical-lift-path still determine the best machine for a given job.
All skid steers come from the factory weighted disproportionately on the rear axle. The machine is more maneuverable and tire wear slows when the front and rear are unequally weighted. Manufacturers' designs vary, but the basic objective is for the skid steer to pivot around the rear wheels when it is unladen, and the front wheels when the loader is handling rated capacity.
Carrying half of a skid steer's gross vehicle weight on the front axle and half on the rear will make it hard to steer, and tire wear will accelerate. Shifting too much unladen weight to the rear axles reduces the down pressure the machine can generate when digging and using attachments like a dozer blade or landscape rake.
Most Bobcats carry about 70 percent of their weight on the rear wheels, although longer-wheelbase, vertical-lift-path machines shift more toward 65/35. Caterpillar and Case tend to design with similar weight distributions. John Deere and New Holland build machines with weight distribution more in the 60/40, front-to-rear, range.
Variations in design offer buyers balance choices to suit their specific applications. If tire wear or precise maneuvering is a problem for users of machines with 60/40 weight distribution, it may be worth trying one that carries 70 percent of its weight on the rear wheels. If inadequate down force is a challenge to users of machines with 70/30 weight distribution, there may be benefits in machines that put more of their load on the front.
Choosing a vertical-lift-path machine will influence how much the loader can lift.
"No matter how you slice it, a machine with vertical lift path will have higher rated operating (ROC) capacity than a similar machine with radial lift path," says Mike Fitzgerald, Bobcat loader specialist. "Our S220 compares to an S250 when you go with the vertical lift path configuration. It's a 300-pound gain in ROC."
For about an $1,800 premium (adding vertical lift to the roughly $34,000 purchase of a Bobcat S220), vertical lift linkage frees the loader arm from a fixed rear pivot and mounts it in a four-link scissor configuration. Manufacturers mount stabilizer links and cylinders differently, but the object remains: Convert the radius lift path — where the load rises in an arc and is farthest from the skid steer's center of gravity at mid lift, right where the operator needs maximum stability for loading pallets on flat-bed trailers — to a straight vertical lift.
Electro-hydraulic controls, currently available as an option on Bobcat, Cat, and John Deere skid steers, also promise refinement in how the loader lifts loads. But initial advantages of the technology have been more limited to improving travel. Electronic-over-hydraulic controls convert joystick movement into digital signals received by an on-board computer that communicates with the hydraulic system.
The power of the computer, mysterious as it may seem to some, is prodigious. Bobcat and Caterpillar offer speed management with their electronically controlled machines. The operator can select a maximum speed setting on a dial and the machine will not exceed that speed no matter how far the operator moves the ground-drive lever. The operator no longer has to hold the joystick at a precise intermediate angle to move at a desired speed.
Trying to crowd too much asphalt into a cold planer or cut too much trench by traveling too fast can stall the engine and damage the tool. "Speed Management allows you to set the loader's maximum travel speed to achieve the sweet spot — the speed where both the attachment and the loader perform most efficiently," says Fitzgerald.
Bobcat's Speed Management mode offers a choice of settings that represents a percentage of the skid steer's 7-mile-per-hour top speed. If you choose 50 on the dial, "no matter how far you move the joystick, the loader won't travel faster than around 3.5 miles per hour, which is about 50 percent of full speed," Fitzgerald says. "This allows you to maintain maximum driveline torque to power the wheels or tracks and full hydraulic power to operate your attachment."
In Speed-Management mode, moving the joystick a given distance results in a smaller speed change than throwing the lever the same distance in standard mode. Precise control of machine movements becomes much easier, which can add fine control for loading the machine on a trailer, hooking up attachments, working in confined areas, or other such jobs.
Caterpillar's Selectable Work Speed Control comes with the Advanced Machine Information Control System (AMICS). Another AMICS feature is the Selectable Implement Control. The system offers three levels of loader control, giving the operator the ability to adjust how quickly loader functions respond to joystick movement. Control can be tailored to match the operator's preferences.
Cat's Speed Sensitive Ride Control (SSL) is another option made possible by AMICS. It is a ride-control system much like that used on Cat's large wheel loaders, applying the lift cylinders to cushion the load, prevent spillage, and give the operator a smoother ride.
Of course, other skid steers are available with the hydraulic ride-control, but because SSL is an electronic system, its performance can easily adapt to changing ground speed. At high speeds, Cat's ride control automatically engages and allows the loader arms to float. The system turns off at low speed so the boom is rigid for digging and load-placing stability. The end result is faster cycle times.
John Deere is relatively new to using electronic joysticks in skid steers, announcing availability of E-H controls on its large-framed loaders and compact track loaders in January of 2008. But Gregg Zupancic, skid steer product manager with John Deere, promises the company will quickly match feature offerings of the technology's earliest adopters.
One great advantage of electronic controls is that systems already in the field can be upgraded with new features simply by changing software. A service technician can plug a portable computer into the machine's on-board computer and download a programming change. Machine owners get the latest features without paying for new hardware.
Making electronic controls optional features allows buyers who prize simplicity, such as rental fleets, to continue to save money on simpler hydraulic controls. Manufacturers such as Case and New Holland, Gehl/Mustang, Volvo, and JCB continue to offer manual controls (levers connected directly to the spools on hydraulic valves that regulate main-system flow) as standard equipment, with the option to upgrade to pilot-hydraulic controls to reduce lever effort. Pilot hydraulics employ a low-pressure hydraulic circuit between the control lever and valve. The pilot circuit acts on the valve's spools, assisting the operator's lever pressure.
All manufacturers are racing to market skid-steer cockpits that will offer operators a uniquely comfortable place to work. Size of the entry, and expanse of clear glass or grid to look through on the sides and top of ROPS continue to grow. Suspension seats are becoming standard equipment in many lines, and even heated air-ride seats are now offered as options in a couple of makes' enclosed cabs. This generation of operator-restraint bars is becoming ergonomic, with wider bars designed to offer operators more room and arm rests.
"Operator comfort is a big factor in productivity," said Jim Hughes, marketing manager with Case. The goal is not to coddle operators, but to keep them fresh and productive over more time in the seat. "That's why Case is always striving to improve the operator's platform when designing and upgrading models."
Manufacturers aren't neglecting reliability as they focus on skid steer productivity. Case's new Tier-3 skid steers come with oversized, wide-fin radiator and oil cooler (sized for high-flow auxiliary hydraulics) mounted side by side rather than stacked to improve air flow. Bobcat's largest Model S330 (introduced in January 2007) incorporates what the company calls SmartFan — a thermostatically controlled, variable-speed cooling fan driven by a hydraulic motor that only turns as fast as necessary to maintain optimum coolant temperature. Noise and horsepower drain are both reduced.
As skid-steer capacity creeps up, a refined evaluation of large-frame loaders can help buyers carve new revenue streams with machines rated to handle 2,200 pounds or more. Nine machine models (from Bobcat, Case, John Deere, Caterpillar, Gehl and Mustang) can work with loads from 3,000 to 3,850 pounds. They will reach over sideboards 125 to 142 inches high, and drive hydraulic attachments with auxiliary flow rates of 33 to 41 gallons per minute. These big machines can compete with small wheel loaders for some production work. Buyers who want to wring productivity out of their over-$50,000 loaders can maximize their investments with any number of high-end options.
|Big Skid-Steer Costs|
|Size||List Price||Hourly Rate|
|Source: "Contractors Equipment Cost Guide" by Equipment Watch - 800/669-3238|
|2,201 to 2,500 lb.||$33,401||$30.41|
|> 2,500 lb.||$39,810||$35.20|
|Big Skid-Steer Specifications|
|Model||Rated load, standard (lb.)||Bucket breakout (lbf)||Net horse-power||Pump flow (gpm) standard/optional||Operating weight (lb.)|
|New Holland L180||2,200||6,034||59||19.3/34.7||7,095|
|Bobcat S220 K-Series||2,200||6,550||74.9||20.7/40.5||7,470|
|Gehl 5640E Turbo||2,200||5,900||82||23/36||7,380|
|Doosan 460 Plus||2,250||4,678||65||21.7/32.3||7,174|
|JCB 1110 Wheel Robot||2,425||4,630||82||20/32||8,214|
|Caterpillar 252B Series 2||2,500||5,508||70||22/na||7,861|
|John Deere 325||2,500||7,500||70||22/34||8,390|
|New Holland L185||2,500||7,670||72||19.3/34.7||7,100|
|Bobcat S250 K-Series||2,500||6,840||74.9||20.7/41.4||7,723|
|John Deere 328||2,750||10,500||76||22/36||8,580|
|New Holland L190||2,800||7,670||74||21.9/37.3||7,755|
|Bobcat S300 K-Series||3,000||6,840||81||20.7/40.5||8,140|
|Bobcat A300 K-Series||3,000||7,150||81||20.7/37||8,673|
|John Deere 332||3,175||11,600||85||24/41||9,160|
|Bulldog www.bulldog-usa.com||Case www.casece.com|
|Caterpillar www.cat.com||Gehl www.gehl.com|
|JCB www.jcb.com||John Deere www.deere.com|
|Komatsu www.komatsuamerica.com||Mustang www.mustangmfg.com|
|New Holland www.newhollandconstruction.com||Thomas www.thomasloaders.com|