I want to add an electric motor to my 8Freight cargo bike but the frame geometery does not allow for the usual Bafang / Tongsheng kits that fix around the bottom bracket. Wheel motors are not an option but I did see a motor that fitted to one end of the crank. Admitedly it looked a bit odd but the owner was pleased with it and praised its 'German reliability'. Does anyone have an idea what this motor is?