A pedaled drivetrain includes a drive mechanism, a wheel, a freewheel hub, and a locking mechanism. The wheel has a rotational axis. The freewheel hub connects the drive mechanism to the wheel, and the freewheel hub transmits torque from the drive mechanism to the wheel in a first rotational direction around the rotational axis. The locking mechanism has a locked state and an unlocked state. The locked state rotationally fixes a component of the drive mechanism to the wheel relative to the rotational axis.

A pedaled drivetrain includes a drive mechanism, a wheel, a freewheel hub, and a locking mechanism. The wheel has a rotational axis. The freewheel hub connects the drive mechanism to the wheel, and the freewheel hub transmits torque from the drive mechanism to the wheel in a first rotational direction around the rotational axis. The locking mechanism has a locked state and an unlocked state. The locked state rotationally fixes a component of the drive mechanism to the wheel relative to the rotational axis.

A pedaled drivetrain includes a drive mechanism, a wheel, a freewheel hub, and a locking mechanism. The wheel has a rotational axis. The freewheel hub connects the drive mechanism to the wheel, and the freewheel hub transmits torque from the drive mechanism to the wheel in a first rotational direction around the rotational axis. The locking mechanism has a locked state and an unlocked state. The locked state rotationally fixes a component of the drive mechanism to the wheel relative to the rotational axis.

A pedaled drivetrain includes a drive mechanism, a wheel, a freewheel hub, and a locking mechanism. The wheel has a rotational axis. The freewheel hub connects the drive mechanism to the wheel, and the freewheel hub transmits torque from the drive mechanism to the wheel in a first rotational direction around the rotational axis. The locking mechanism has a locked state and an unlocked state. The locked state rotationally fixes a component of the drive mechanism to the wheel relative to the rotational axis.

A transmission system, such as for a two wheeled bicycle, including an axle assembly including a set of sprockets, a transmission unit having an input coupled to the set of sprockets and an output arranged to be coupled to a wheel. The transmission unit includes a transmission operable according to a first transmission ratio and a second transmission ratio, a clutch or brake system for switching from the first to the second transmission ratio under load, and a first actuator for controlling the clutch or brake for coupling or decoupling. The transmission system including a second actuator for selecting one of the sprockets for transmission of torque to the axle assembly, and a controller configured to receive a first shift signal and/or a second shift signal, and configured to control the first actuator and/or the second actuator in response to the first or second shift signal.

A transmission system, such as for a two wheeled bicycle, including an axle assembly including a set of sprockets, a transmission unit having an input coupled to the set of sprockets and an output arranged to be coupled to a wheel. The transmission unit includes a transmission operable according to a first transmission ratio and a second transmission ratio, a clutch or brake system for switching from the first to the second transmission ratio under load, and a first actuator for controlling the clutch or brake for coupling or decoupling. The transmission system including a second actuator for selecting one of the sprockets for transmission of torque to the axle assembly, and a controller configured to receive a first shift signal and/or a second shift signal, and configured to control the first actuator and/or the second actuator in response to the first or second shift signal.

A power transmission unit for electric bicycles includes an input structure, an output structure, a torque detection unit, a detection target, and a detection unit. The input structure includes an input shaft. The input shaft is caused to rotate by external force transmitted thereto. The input structure rotates along with the input shaft. The output structure outputs rotational power by rotating along with the input structure. The torque detection unit is provided on an outer periphery of the input structure. The detection target rotates either along with, or while interlocking with, the input structure. The detection unit detects a rotational state of the detection target. At least part of the torque detection unit and at least part of the detection target overlap with each other when viewed perpendicularly to a rotational axis of the input structure.

An electric assist device for a bicycle comprising a shaft coupled in rotation with a pair of cranks and being able to be rotated in a positive direction by an electric motor, a connection mechanism being placed between the motor and the shaft, which connection mechanism has at least three distinct states. The states includes State 1, termed assist state, in which the motor transmits a torque to the shaft via a drive part which rotates at the same speed as the shaft, State 2, termed freewheel state, in which the rotation of the shaft in the positive direction is greater than that of the drive part, and State 3, termed disconnection state, in which a rotation in the positive direction or in the negative direction of the shaft cannot cause the motor to rotate.

An electric assist device for a bicycle comprising a shaft coupled in rotation with a pair of cranks and being able to be rotated in a positive direction by an electric motor, a connection mechanism being placed between the motor and the shaft, which connection mechanism has at least three distinct states. The states includes State 1, termed assist state, in which the motor transmits a torque to the shaft via a drive part which rotates at the same speed as the shaft, State 2, termed freewheel state, in which the rotation of the shaft in the positive direction is greater than that of the drive part, and State 3, termed disconnection state, in which a rotation in the positive direction or in the negative direction of the shaft cannot cause the motor to rotate.

A sprocket support body comprises at least ten external spline teeth including a plurality of external-spline driving surfaces. The plurality of external-spline driving surfaces each includes a radially outermost edge, a radially innermost edge, and a radial length. A total of the radial lengths of the plurality of external-spline driving surfaces is equal to or larger than 7 mm. At least one external-spline driving surface has a first external-spline-surface angle. The first external-spline-surface angle ranges from 0 degree to 10 degrees. One tooth of the at least ten external spline teeth having a first circumferential spline size. The other teeth of the at least ten external spline teeth each have a second circumferential spline size that is smaller than the first circumferential spline size. A total number of the other teeth of the at least ten external spline teeth being equal to or larger than nine.