If you did get the rear wheel kit Make sure you get a good freewheel the first time.When I installed my Rear BionX kit I got the IRD freewheel from Harris cyclery All the other ones I tried where bad. I would have liked to use a Suntour but they were to much money.The IRD is the best bang for the buck If you are running a 9 speed a 7 or 8 will work with a rear DR adjustment A 9 might be too wide for your spacing With Electric you will not use all the gears anyway