Remove all the screws in the rim on both sides.
Grab the wheel by its tire and give the axle on the non cable side a good hit against a piece of wood or a workbench.
This will start separating the upper rim on the cable side from the tire. It takes some effort.
Once it starts to separate you will get an idea of how hard you have to hit the wheel.
Remember we are doing it against wood. NOT concrete or metal.
Once it separates you can remove one rim side including the motor and the bottom rim stays inside the tire.
Hold the tire in one hand and use a rubber mallet to bang out the remaining rim from the inside of the tire.
Here is a video: https://drive.google.com/open?id=1OQ2sGaZPdann__ulruur_xcTfGdy7OsS