Bicycle drive unit

A bicycle drive unit comprising:

• a housing configured to be mounted on a frame of a bicycle, the housing including a first portion and a second portion;
• a crankshaft provided to the first portion of the housing;
• a propulsion assist motor provided to the second portion of the housing and configured to assist propulsion of the bicycle, the propulsion assist motor including a rotational axis extending in a direction intersecting a direction in which the crankshaft extends;
• an output part provided to the housing, the crankshaft and the propulsion assist motor being operatively coupled to the output part to transmit torque from the crankshaft and the propulsion assist motor to the output part;
• and
• a decelerator provided to the housing and connected to the propulsion assist motor,
• the second portion having a maximum dimension of smaller than or equal to 75 mm in a direction orthogonal to the rotational axis of the propulsion assist motor,
• the decelerator including a first gear, to which the torque of the propulsion assist motor is transmitted, and a second gear engaged with the first gear to transmit the torque to the output part,
• the first gear including a first rotational axis parallel to the rotational axis of the propulsion assist motor;
• and
• the second gear including a second rotational axis parallel to the rotational axis of the crankshaft.