Originally Posted by
Rick
There is a lack of pertinent info in your advice. There are some reasons that this could happen. The main one that happens to come to mind. is due to poor fitment of the hub motor axle it was allowed to spin in the fork and twist the power cable and pull itself from the fork. poor fitment of hub motor axles is common. Most front hub motor axles are 12mm diameter with 10mm flats ground in them. There usually needs to be some filing of the openings in the stays so the axles will fit. The smaller hub motors use the stay opening with a type of tabbed washer as the torque arm. If the axle bolts work loose or the filing is not done properly or both. The force can cause the opening in the stays to spread and the axle to rotate. The power going through the motor can be excessive enough for this to be a problem. Even with a torque arm ...
There is only one reason this happened, and you only touch on it, almost in passing: the lack of torque arms (two) allowed the motor to destroy the fork. Beginning and end of story. The Grin All Axle Hub Motor is a pretty nice piece of kit, and you are pretty sold on it, but I haven't seen the post where you tell people how much it costs! You might be prepared to take on a motor, a wheel build, a suitable controller/display, and battery, for a total cost well exceeding $2K, but that would not be everyone. And it is terribly incongruous for someone as well informed on the subject as you clearly are, to use 'breaking' when you mean 'braking'.