A harmonic pin ring gear system comprises an input shaft, an output shaft, two outer gears each with internal toothing and a single inner gear with external toothing. The inner gear is arranged concentrically to a first outer gear and in axial direction inside the first outer gear. A drive means extends between the two outer gears and the inner gear and comprises a pin-retaining ring formed as one part in circumferential direction and a multiplicity of pins that protrude laterally in axial direction from the pin-retaining ring. A rotary transmitter lifts the drive means off the external toothing of the inner gear and presses the drive means into the internal toothing of the outer gears.