Method for controlling a drive device of a bicycle, wherein the drive device comprises a planetary gear, an actuating electric motor and a speed reduction gear, wherein the actuating electric motor is engagingly connected to a first input component of the planetary gear by means of the speed reduction gear and the pedal axle of the bicycle is connected for conjoint rotation or engagingly to a second input component of the planetary gear, and an output component of the planetary gear different from the input components (223, 224) is connected, for conjoint rotation, to an output pinion of the drive device, said method comprising the following method steps • detection of a speed of the pedal axle, and • generation of an actuating motor speed by means of the actuating electric motor based on the detected speed of the pedal axle in order to set a transmission ratio of the planetary gear between the pedal axle and the output pinion, wherein the actuating motor speed is adjusted within a time period of less than or equal to twenty milliseconds after a change in the detected speed of the pedal axle and • wherein the planetary gear is arranged coaxially around the pedal axle, • the pedal axle is connected for conjoint rotation to the planetary carrier of the planetary gear, • the actuating electric motor is connected engagingly to the hollow shaft of the planetary gear by means of the speed reduction gear, wherein the hollow shaft additionally has an external toothing, and • the sun gear of the planetary gear is arranged for conjoint rotation on a hollow output shaft running coaxially around the pedal axle and said hollow output shaft is connected for conjoint rotation to the output pinion of the drive device, said method being characterized by the following steps: • detection of an input from the cyclist for desired manual operation without electrical assistance, and/or • detection of a current state of charge of a battery module of the bicycle, and • fixing of the hollow shaft of the planetary gear by means of a brake disc, which is connected for conjoint rotation to the hollow shaft, based on the detected input from the cyclist for desired manual operation and/or based on the detected current state of charge of the battery module, by means of a brake. • detection of a speed of the pedal axle, and • generation of an actuating motor speed by means of the actuating electric motor based on the detected speed of the pedal axle in order to set a transmission ratio of the planetary gear between the pedal axle and the output pinion, wherein the actuating motor speed is adjusted within a time period of less than or equal to twenty milliseconds after a change in the detected speed of the pedal axle and • wherein the planetary gear is arranged coaxially around the pedal axle, • the pedal axle is connected for conjoint rotation to the planetary carrier of the planetary gear, • the actuating electric motor is connected engagingly to the hollow shaft of the planetary gear by means of the speed reduction gear, wherein the hollow shaft additionally has an external toothing, and • the sun gear of the planetary gear is arranged for conjoint rotation on a hollow output shaft running coaxially around the pedal axle and said hollow output shaft is connected for conjoint rotation to the output pinion of the drive device, said method being characterized by the following steps: • detection of an input from the cyclist for desired manual operation without electrical assistance, and/or • detection of a current state of charge of a battery module of the bicycle, and • fixing of the hollow shaft of the planetary gear by means of a brake disc, which is connected for conjoint rotation to the hollow shaft, based on the detected input from the cyclist for desired manual operation and/or based on the detected current state of charge of the battery module, by means of a brake.