I have a Fatte-Bike SGT. Mingo in the pipeline for sometime in May. It'll be their first bike delivered in an XL frame size - about 21.6". It comes with a Bafang 750 Watt Nominal geared motor. I want something in the neighborhood of 1500 Watts nominal with peaks to 2000 Watts. I found a Direct Drive 1500 Watts Nominal RiSunMotor laced into a 26" x 4" Blue Anodized wheel with 175mm Drop Out spacing online. I wanted a way to test it out before leaving feedback and was thinking about how to secure it for a test run since I don't have a bike with 175mm dropouts. My wife happened to be donating her 2003 Raleigh beach cruiser which has been in a bike trainer stand for years. I suddenly saw my motor testing stand. I machined a few countersink points to insert into the stands' pinch bolts and which fit into the ends of the motor axle. Then I found a 36" long piece of 3/4" thick by 2.5" wide aluminum bar I had laying around and machined a .384" wide groove in the end of it to create an almost press-fit over the axle flat to act as an Anti-Torque arm.
Hooked up a Lyen sensorless controller to my Prodeco 51V pack and a spare throttle and away she went. Turns exactly 700 RPM full throttle, unloaded according to my optical tach.