A robust system designed to allow maximum flexibility in bicycle architecture with even less wear: With “Bike-by-Wire”, automotive supplier Schaeffler has developed an electric drive system that manages without any connection between pedals and wheel.
The “Bike-by-Wire” chainless drive system is a joint development by automotive supplier Schaeffler and two-wheel e-drive specialist Heinzmann GmbH & Co. KG and dispenses with a mechanical connection between the generator and the motor. This means that neither a bicycle chain nor a toothed belt is used between the pedals and the driven wheel. This makes entirely new bicycle architectures and pedal configurations possible, with even less need for wear parts at the same time.
The central component of the Free Drive system is the generator from Schaeffler, which adjusts the uniform resistance at the pedal and simultaneously absorbs the pedalling power of the driver. The recuperative solution is a serial hybrid drive and converts the mechanical energy generated by pedalling into electrical energy, which in turn is converted back into mechanical energy in the wheel hub motor.
Surplus energy is stored in the battery. All system components communicate with each other via CAN connection, just like in a car. Optimally coordinated, the overall system consists of a pedal generator, drive motor, battery power pack and human-machine interface (HMI). Without the mechanical connection of generator and motor, the Free Drive system is intended to offer maximum flexibility in bicycle architecture and a freely configurable pedal feel, adapted to the requirements of the bike and needs of the rider with low wear. The compactness of the Free Drive allows a common distance between the two pedals of 138 millimetres.
Even if the system will initially be used primarily in heavy transport bikes, the technology behind it is very exciting. The same applies to the question of whether such a system is even compliant with the pedelec guidelines — pedalling without a motor at speeds above 25 km/h is hardly possible. But Schaeffler will certainly give this some thought, and who knows, maybe in a few years there will actually be “normal” e-bikes with “bike-by-wire”.