I keep Sunrace 8-speed 11T-28T freewheels. The OP had originally 9-speed cassette, so either he buys a 7-speed shifter and put up with 13T sprocket or 9-speed freewheel and a freewheel tool with thin wall. BTW, what do you think of Mechaniker's torque sensor that he builds into the freehub?
I've got a feeling that it's too expensive and complicated for what I'd want. As you know, I like the KT pedal assist control system a lot, and you can have a throttle with it that works independently to 4 mph, then works after that as long as the pedals are turning. The response time is very quick, so a torque sensor won't give a big advantage on that, if any at all. The one thing I wouldn't want is any system that uses torque multiplying algorithms, where you pedal harder to get more power. That seems daft to me. I can understand using a torque sensor as a switch, but in that case all you need is an idler wheel on the chain with a spring to hold it down a bit.
These comments are in relation to using an ebike on the road for touring, commuting, shopping and things like that. For off-road and any sort of difficult terain, a torque multiplying system would be better, but then a hub-motor might not be the best motor either. Mechaniker didn't mention whether his system is a torque multiplyer or fixed power levels.
What about your kit? Does it use torque multiplication or does it give a fixed power or speed for each pedal assist level?
