A radial piston device includes a housing and a pintle fixed thereto that includes an inlet and an outlet, each aligned with a pintle axis. A rotor is rotatably disposed around the pintle and includes radially oriented cylinders. A piston is axially displaceable in each cylinder and includes a head defining a spherical contact surface. A thrust ring is rotatably disposed within the housing about the rotor and is in contact with each piston, such that a rotation of the rotor rotates the thrust ring. An inner surface of the thrust ring defines a toroidal contact surface. A contact location between the spherical contact surface and the toroidal contact surface varies as the rotor rotates about the pintle. A drive shaft is engaged with the rotor, such that a rotation of the rotor rotates the drive shaft.