A hydraulic radial piston device comprising: a housing having a hydraulic fluid inlet and a hydraulic fluid outlet; a pintle shaft fixed within the housing, the pintle shaft defining a pintle inlet and a pintle outlet, the pintle inlet being in fluid communication with the hydraulic fluid inlet, and the pintle outlet being in fluid communication with the hydraulic fluid outlet; a rotor mounted on the pintle shaft and configured to rotate relative to the pintle shaft about a rotor axis of rotation, the rotor axis of rotation extending through a length of the pintle shaft, the rotor defining a plurality of radially oriented cylinders and a plurality of rotor fluid ports, each of the plurality of rotor fluid ports being in fluid communication with at least one of the plurality of radially oriented cylinders and being alternatively in fluid communication with either the pintle inlet or the pintle outlet as the rotor rotates relative to the pintle shaft about the rotor axis of rotation; a plurality of pistons received in the plurality of radially oriented cylinders, respectively; a thrust ring disposed about the rotor and having a thrust ring axis of rotation, the thrust ring being in contact with the plurality of pistons and configured to rotate about the thrust ring axis of rotation as the rotor rotates relative to the pintle shaft about the rotor axis of rotation; and a ring displacement mechanism configured to move the thrust ring through a range of movement within the housing between a first position in which the radial piston device has a minimum displacement of hydraulic fluid per each rotation of the rotor and a second position in which the radial piston device has a maximum displacement of hydraulic fluid per each rotation of the rotor, characterized by: the ring displacement mechanism maintaining the thrust ring axis of rotation in offset relation relative to the rotor axis of rotation throughout the range of movement of the thrust ring within the housing. a housing having a hydraulic fluid inlet and a hydraulic fluid outlet; a pintle shaft fixed within the housing, the pintle shaft defining a pintle inlet and a pintle outlet, the pintle inlet being in fluid communication with the hydraulic fluid inlet, and the pintle outlet being in fluid communication with the hydraulic fluid outlet; a rotor mounted on the pintle shaft and configured to rotate relative to the pintle shaft about a rotor axis of rotation, the rotor axis of rotation extending through a length of the pintle shaft, the rotor defining a plurality of radially oriented cylinders and a plurality of rotor fluid ports, each of the plurality of rotor fluid ports being in fluid communication with at least one of the plurality of radially oriented cylinders and being alternatively in fluid communication with either the pintle inlet or the pintle outlet as the rotor rotates relative to the pintle shaft about the rotor axis of rotation; a plurality of pistons received in the plurality of radially oriented cylinders, respectively; a thrust ring disposed about the rotor and having a thrust ring axis of rotation, the thrust ring being in contact with the plurality of pistons and configured to rotate about the thrust ring axis of rotation as the rotor rotates relative to the pintle shaft about the rotor axis of rotation; and a ring displacement mechanism configured to move the thrust ring through a range of movement within the housing between a first position in which the radial piston device has a minimum displacement of hydraulic fluid per each rotation of the rotor and a second position in which the radial piston device has a maximum displacement of hydraulic fluid per each rotation of the rotor,