I have done a little research and I think I now have the right idea for my big finish e bike. Drum roll please. What I have now is a 350 watt brush motor on a mount that is part of the rear wheel assembly. The wheel is 12.5 inches in diameter and the sprocket is a fast 55 tooth 4.5 inch model. The bike has a coaster 20" rear wheel. I have done some research and found there is a 500 watt or larger motor that will fit onto the wheel housing, That should give me better sustained speed going uphill. I have a ton of 26" mountain bike rear wheels sitting around. Most are in good condition. I can pick up a solid 26" mountain bike frame for peanuts from the thrift store. I will just convert it to a one speed, that's all you really need anyway with a motor bike. Add my upgraded pusher motor that is already scary fast and I should have the final version of my ebike. I have no plans to start on it today, but that is what I plan to make my final ebike version when I get around to it. If I set it up right the whole pusher assemble will fold up over the rear wheel of the bike for easy roll around and storage. I would simply have to drop it and ride off. It's all I do now with my pushers. The batteries make them heavy nothing else.