Propulsion device for a bicycle

A propulsion device for a bicycle, comprising:

• a mounting assembly for releasably coupling the propulsion device to the bicycle;
• a motor;
• a power source operably coupled to and selectively providing power to the motor;
• a gear assembly coupled to the motor;
• and
• two frictional drive components coupled to the gear assembly, the two frictional drive components being movable between an engaged configuration and a disengaged configuration, wherein in the engaged configuration the two frictional drive components are frictionally engaged with a side of a wheel of the bicycle such that the wheel is arranged between the two frictional drive components and in the disengaged configuration the two frictional drive components are disengaged from the wheel,
• wherein:
• when the power source provides power to the motor, the motor drives the gear assembly:
• (i) to move the two frictional drive components into the engaged configuration, and (ii) to rotate at least one of the two frictional drive components such that rotation of the at least one frictional drive component rotates the wheel of the bicycle, and
• the gear assembly comprises:
• a gear housing;
• a planetary gear assembly coupled to the gear housing and including a ring gear, a sun gear, and a plurality of planet gears;
• and
• one or more drive gears coupled to the at least one of the two frictional drive components, wherein the one or more drive gears are coupled to the planetary gear assembly through the sun gear.