The other idea is that a magnet as the driving force for magnetic flux,would work better than brute force originated by copper coils.
Due to missing magnets you can overheat it more than a synchronous motor.
The only limit is the isolation of the wires, this is usually like 200 degrees Celsius vs around 100 degrees for magnets, after which the magnets become useless pieces of metal.
A high pole count axial-flux motor would not need an iron core. Using nothing but copper and made extremely thin, would be very highly efficient because there is no hysteresis. And no cogging effect.
Basically you are attempting to create a CSIRO / Launchpoint like motor, but with even higher pole counts. (60+ poles?) The higher pole counts allows for lower rpm operation which is necessary for human pedaling cadence. A Halbach Magnet configuration focuses the magnetic forces within the motor and removes the need for iron.