I'm still in the initial stages of my research into electric bikes and was curious if the following was even possible or reasonable to think about. I'm thinking about a hub motor conversion kit for my mountain bike, but I'd still like to use it for "normal" biking from time to time as well. Is it reasonable to think about swapping between an electric motor wheel and a normal bike wheel? Obviously this works better when the motor is mounted on the front wheel, but I'm not clear if my Rock Shox Jett fork can withstand the torque such a motor exerts. If I have a rear wheel with the same gearing as my normal wheel, does that make things easier? Or would I still be messing with my rear derailleur every time I switched wheels?
I have found with the Amped kit that the wheel is displaced about 5mm to the left with the motor. I had to seriously adjust the brakes to get it in, and wouldn't relish the thought of swapping wheels to ride regular. When I was first researching I thought it would be a good idea. Quite honestly, the bike is heavy with the motor, but without the battery it's really not that big of a deal for me. I don't know what material your fork is made of, but I have heard that if they are steel, even though they have suspension, they would work. Just use a couple of torque arms! It would be a far easier swap from the front. You would probably also want to use removable zip ties to hold the cables against your frame, otherwise you'll be cutting them (or electrical tape, as I used) every swap you made. To reduce the stress on the frame, get yourself up to speed first by pedaling, then hit your throttle to maintain/accelerate a little. I cannot speak to the lateral shift of other kits, perhaps they are not as bad. My frame is a Trek hybrid, 700c tires so there wasn't quite as much room for error to begin with. You can get freewheels with various numbers of cogs, so you'll be able to get the same number of gears as you already have.