I've had a Shimano hub for about four years. The Shimano connector has the wires wrapped vertically around a center "plate" with channels for the wires, and an outer plastic shell that locks into the center plate. It looks like it should be a problem, but in practice, it hasn't been. I simply twisted each wire before closing the shell, and it's held so far.


If the SP hub has a similar arrangement, you might try stripping twice the length that's actually necessary, wrap the wire down and back, and then twist it around itself. If you think about it far enough in advance, you could solder the self-wrapped wire and use heat shrink tubing to hold the joint and insulate it.