Using a small brushed DC motor together with a larger BLDC motor can provide strong acceleration combined with good high rpm power. The brushed DC motor provides initial torque to get the bike ...

“Another BLDC motor controller ... MLX90363 hall effect sensor to locate the rotor position. Simply glue a small magnet to the shaft, calibrate the magnetic field with one revolution ...

settled on with his BLDC rewinding and rewiring project ... He started with a teardown of a small motor, to understand the mechanical challenges involved, then moved onto a larger motor.