In addition to losing attachment productivity, using a skid-steer that can't provide the optimum hydraulic system requirements places greater stress on the unit. "Operating a loader at the maximum flow and pressure for long periods of time can result in excessive heat," says Moore.

Hydraulic systems are designed with relief valves to protect them from such abuse. However, Hughes, notes, "If you are constantly going over relief, you will be creating heat, which will ultimately damage the hydraulic system and the powertrain."

"If the machine has more flow and the attachment does not have the proper flow bypass, heat could be created and potentially cause motor and seal failures," says Gregg Zupancic, product marketing manager, John Deere Construction. "If the machine has less flow than the attachment requires, then the attachment may not run at optimal performance and it can potentially cause unnecessary failures to mechanical or structural parts of the skid steer and attachment. A good example would be a cold planer. If the drum is not spinning at optimal speed, it would tend to chuck the surface and cause unnecessary machine bounce or attachment vibration."

Jorge DeHoyos, brand marketing manager for New Holland Construction, adds, "Attachments typically list minimum and maximum flows and pressures. Using the wrong attachment can cause physical damage and premature wear on both the skid steer and attachment. Using a cold planer with a lower than required flow capacity, for example, will lead to premature breakage and wear on the cutting tips. Using an auger that requires more flow than provided will overheat both the attachment and skid steer, since the oil runs through both."

But there are measures other than flow and pressure that can affect hydraulic performance. "Another critical item to check is back pressure of the skid-steer loader," says Hughes. "High back pressure robs performance because the machine is working harder to return the oil to the tank."