Some skid steer attachments have a higher demand for hydraulic horsepower than others. Take, for example, a cold planer milling concrete versus a brush cutter cutting grass. The cold planer is going to need more horsepower than the brush cutter. This extra horsepower will come from a higher hydraulic flow rate.

A higher hydraulic flow rate increases hydraulic horsepower when pressure remains constant. The formula to represent this is: Gallons Per Minute (GPM) times Hydraulic pressure in pounds per square inch (PSI) divided by 1,714 equals hydraulic horsepower. For example, a standard flow skid steer with 17GPM of hydraulic flow at 3,500 PSI will produce around 34HP, while a 40GPM high flow skid steer at the same 3,500 PSI will produce over 80HP of hydraulic power. Horsepower is the measuring stick for how much "work" is getting done in a set amount of time. When you need an attachment with high horsepower, you increase the hydraulic flow rate to the motor, and that's how you end up with a high-flow attachment!