An infeed system is provided for a chipper or grinder having a processing portion wherein an item is processed into smaller pieces. The infeed system is upstream of the processing portion and includes a feed roller, a first hydraulic motor in communication with the feed roller for selectively actuating the feed roller, a second hydraulic motor in communication with the feed roller for selectively actuating the feed roller, and a hydraulic pump for providing hydraulic fluid to the first and second motors. A directional control valve and a relational control valve are between the pump and the motors. The directional control valve allows the hydraulic fluid to operate the first and second motors in a forward direction and in a reverse direction, and the relational control valve allows the hydraulic fluid to operate the first and second motors in series and in parallel.
