Thanks for your idea's, the only problem I have is that the other side of the wheel hub has a drum brake which I would like to keep as it's very powerful even in wet conditions. All the kits I've looked at for rear wheel drive have a sproket with a standard 20-25 centre hole to go over a conventional wheel hub, does anyone know where a larger hole centered sproket can be obtained from? I was wondering if this type of kit could be applicable?