Bicycle torque sensor

An electric bicycle drive unit for arrangement in a bottom bracket region of a bicycle frame, the drive unit comprising:

• a torque sensor device,
• a bottom bracket shaft,
• an electric motor device arranged coaxially to the bottom bracket shaft,
• a hollow output shaft transmitting a motor torque and a rider total torque to a bicycle drivetrain, and
• a rider moment coupling device arranged between the bottom bracket shaft and the hollow output shaft for transmitting the rider total torque between the bottom bracket shaft and the hollow output shaft, and
• a motor torque coupling device arranged between the electric motor device and the hollow output shaft for transmitting the motor torque to the hollow output shaft,
• wherein an axial region of the hollow output shaft is configured to transmit both the rider total torque and the motor torque, wherein the torque sensor device defines an axial extent of the axial region and is arranged therein.