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 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 . <EOS>