tolkaNo said:
The theory build i had in mind was the giant dh glory frame, which has 12mm rears, and 3000w qs hub motor with 12mm axles
If it's a 3kw motor, and you run it with a controller capable of using it well, it's likely to have a lot of torque.
All that torque will be applied to the extremely small cross section of axle flat that touches the frame. It doesn't apply any of the torque to anything else, so that's a whole bunch of force in a
fingernail-sized area (or smaller!) doing it's very best to destroy your bike.
If it only has a 12mm axle, that is weak for a motor that size already, and is going to be under stress just from the torque even when properly installed and clamped down.
If you only clamp down one end of it, then that end will be under twice as much stress as it was designed to take, and that much more likely to break.
If the axle itself doesnt' break, then that leaves the doubled stress on the torque plate it's in, and the mountings of the plate to the frame.
If it's not in a torque plate, then it leaves the double stress on the torque arm, whcih is usually thinner than the plate would be, and more likely to deform or cut into the axle and allow it to spin in the frame, damaging the dropouts.
If it's not in a torque plate or torque arm, then the double stress is all on the dropout/frame, which was not designed to handle that at all, and what happens to it depends on how it's made, but it's hardly ever pretty or fun.
I don't know why people sometimes don't want to listen to the voices of experience, even when shown what can happen, until after their own stuff breaks and they crash and get hurt, but it's a continuing thing around here. :/
Up to you how you build your bike, but you can't say we didn't warn you and try to prevent it, when either the axle, the frame, the dropouts break, or the axle spins and rips apart your wires and blows up the controller and/or the motor halls.
It's quite possible that nothing bad will ever happen.
But I wouldn't put my faith in that, after the stuff I've seen on other's bikes and my own.