speedmd said:I think you guys should give a good look at the gear box threads! 3kw is no issue IMO. Trying to drive it through a crankset-jack, yes, a potential issue. Long as you limit the torque, the frames should have little to no issue with this level of power. Why not go motor - direct to rear wheel if you don't care about matching pedal speeds. This size /kv motor should have no issues once you work out the controller side. Would imagine the rotor would stick together well past 8000 rpm.
jdevo i think this should indicate about your selection of beta-tester's rigs themselves, meaning, between all three, there should a huge diversity to accommodate the range you're looking for , where one is free-ride/dh, the other maybe xc, and the last maybe a commuter, and at least one of them should have a rholoff or some other form IGH. otherwise if you end up testing only downhills for example you'll ignore the potential stress and interface to other frame types and components.