auraslip wrote:I noticed that in my fork the stock torque arms that came with my ebike kit are not completely solid, and the axle moves a little bit in between regen braking and acceleration.
*That* you definitely ought to fix, and be absolutely sure it *is* fixed.
Every time the axle can rotate a little in there, it can pry the ends of the dropouts just a little farther apart. Eventually they'll split, and the wheel will come out--depending on exactly how that happens you might get to play hugsy with the road. If you're lucky, the torque arms will prevent that last bit by holding the wheel to the dropouts even if the axle spins out (ripping the wires loose, possibly), but if at all possible, make it so the axle cannot rotate at all, regen braking or hard acceleration or alternating between the two.
Just remember that (especially in front) dropouts were generally not made for the forces of axles torqueing against them, only the upward force of the axle against the fork itself. So without being totally tight and not being able to rotate against the torque arm, the dropouts are being asked to absorb forces they were not designed to take. Sometimes they're strong enough to take that, sometimes they're not. Experimentation on a ride sucks as a method of testing that. Let Justin do all that stuff up at RBC in the lab.
Thankfully I have never experienced this or even seen it in person, but I have certainly seen enough vids and pics of it happening to never ever want to.
It makes me wonder if I could go pick up a motorcycle fork from the junk yard
I got one from Freecycle.org. It's heavier than my whole DGAmkII bike, including the motor and maybe the batteries, but it was free. Only thing wrong with it is a slightly leaky seal on one side for the oil shocks.