Kappstein E-Mobility | Compact OEM Hub-Motor Systems

Kappstein develops compact e-mobility systems for OEM bicycle applications, combining hub-motor architecture, integrated sensing, motor control and drivetrain integration.

B3 - REAR HUB MOTOR

The B3 is a compact direct-drive rear hub motor developed for lightweight e-bike platforms. Despite its small diameter, the motor integrates both the controller and torque sensor within the hub architecture, reducing external system complexity and simplifying vehicle integration.

With a nominal output of 250 W, compact 110 mm diameter and low system mass, the B3 is designed for applications where packaging, acoustic behaviour and clean integration are priorities. The direct-drive architecture eliminates internal reduction gears and supports both chain- and belt-driven bicycle concepts.

The motor features an internal controller and torque sensor. It’s at its best when combined with Kappstein’s Doppio CX bottom-bracket drive system. This enables the construction of an extremely lightweight electric bike with two or more gears using very compact and intelligently designed components. It also sets new standards in e-mobility, especially in terms of performance and innovative content. It’s maintenance-free, permits 9-spline mounting for a cassette or sprocket, and excels with superior heat dissipation.

The B3 is the evolution of the KA Classic motor which in the early 2000s was one of the first BLDC motors in the European market. The majority of ebikes in the European market were equipped with this motor at the time which was distributed under the Toprun brand. Already then it was ahead of its time with an internal controller and torque sensor.

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