I decided the mid drive approach would cause problems with the underseat steering on my EZ3 USX..So I went with a cheap ebay 350 watt kit.. Came with a 20 inch wheel and hub which I installed on the front of the trike.. with no problems. The smaller 20 inch hub gives me a little lower gearing as well. It works very well and I baby it. (no dead stop starts) It will give me about three hours with careful use. It is used for exercise only. I find I use the bike way more than I used to and stay on it longer as well. The entire system came to about 350 including the extra large 20 inch tire for the heavy duty front rim.