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Auxiliary high-flow hydraulic systems can dramatically increase skid-steer loader productivity in the right applications. The higher the horsepower, the more work you can accomplish in a given period of time.

To calculate hydraulic horsepower, you multiply the flow rate in gal./minute (gpm) times the pressure in pounds/sq. in. (psi), then divide by 1,714. So let's assume a skid-steer loader has an operating pressure of 3,100 psi and comes in a 22-gpm standard-flow or a 34-gpm high-flow configuration. Using the above equation, the standard-flow model would provide: (22 gpm x 3,100 psi)/1,714 = 39.8 hp. The high-flow model would offer: (34 gpm x 3,100 psi)/1,714 = 61.5 hp. As you can see, the high-flow unit has quite a bit more capacity to get more work done in a specified time frame.

"With higher hydraulic flow, the loader can provide more performance to power high-flow, high-performance attachments," says Kelly Moore, product manager, skid loaders, Gehl Co. "The increase in productivity is the greatest benefit - being able to perform more work more efficiently and more quickly. For instance, a high-flow trencher or auger attachment coupled to a high flow-equipped loader will run at a faster speed with plenty of torque to avoid stalling in highly compacted materials."

Chris Giorgianni, general manager for product marketing, JCB, states, "The major advantage of a high-flow skid steer is that you have the option to run attachments that require the high hydraulic horsepower and flow, allowing them to run in their optimum performance range. Generally, attachments that require high flow are ones that have a component that needs to be run at a high rate of motion. Examples would be certain varieties of stump grinders, cold planers and slot cutters. A high-flow machine would be of greatest benefit for these, because without the high flow, these types of attachments lose their effectiveness."

"Relatively speaking, the larger a hydraulic attachment, the more flow it will require to engage the ground or spin a drum faster," adds Gregg Zupancic, product marketing manager for skid steers and compact track loaders, John Deere Construction.