Client Case

Perfect measurement of pedal torque in e-bikes


A manufacturer of sensors that measure rotations on the bottom bracket of e-bikes is looking for a system that will enable temperature-independent measurement of the bottom bracket axle. This must be done with the highest possible resolution.


Because of the limited installation space and the accuracy of the measurements, the company wants to place a Hall sensor as close as possible to a magnetic ring with a high polar resolution. The ring must be able to lightly clamp around the bottom bracket axle and may not break.


The customer asked us to develop a ring that can be pressed onto the axle. This ring must be provided with magnetic material. With sufficient magnetic strength to switch the Hall sensor, this magnetic material must provide a high resolution on a 360-degree rotation. In addition, the magnetic material must not crack due to expansion during compression.



Together with its strategic alliance in China, Bakker Magnetics has developed a production process in which a metal ring is coated with a thin layer of thermoplastic magnetic material. That material can be provided with 72 magnetic poles, depending on the diameter.


Through the close cooperation between the customer, Bakker Magnetics and the strategic alliance in China, a product was developed that is resistant to temperature changes and does not crack due to the forces that occur during compression. Due to the high quality, the customer has no downtime during his production process and has gained an advantage over his competitors in the e-bike market.

Bakker Magnetics. Delivering magnetic expertise.