Well, I've convinced my wife that she will be able to ride the USX easier with a Nuvinci and she allowed me to buy the hub. I purchased the trike a month or so ago and haven't really rode it except for around the nieghborhood. I'm taking the project slow and figured if I'm going slow, may as well do it right. I'll be using the non-driven wheel to attach the drive sproket and use the Nuvinci hub as a jack shaft. I'll mount the output sproket to the disk brake mount and will have a free wheel on the Nuvinci so the motor can free wheel on the hills. People have said that because they have a transmission that they went with the GX35, but I think I'm sticking with the big 50, unless of course anyone can give me a reason not to. Only the hub is in the mail, so I have time to change things around. If anyone thinks this will be a bad idea, please let me know. I'll post pics as I go, but that may be a little while. For now, the only thing turning are the gears in my head!:-/