Is one of the differences on a hub bike a narrower bracketing of assist levels?
The Bosch ones are something like 40/100/200/300%.
it's completely different in operating principle. The Bosch has a torque sensor, the output depends on your cadence multiplied by pedal pressure multiplied by user settable assist ratio.
The Rio has only cadence sensor and user defined outputs, independent of cadence and pedal pressure.
You have 6 assists levels: 0, 1, 2, 3, 4, 5. 0 is no pedal assist but the throttle still operates, it suits cyclists who only need ad hoc assistance for hills. All the other levels are user settable in the LCD. The default setting are 50%, 65%, 80%, 90% and 100% of the controller's maximum output which is also set in the LCD. The default is 17A. For example, on assist level 1, the controller will use up to 50% * 36V * 17A = 306W. Of course you don't get all that power while riding on assist level 1, its power limiter is set at that level. The controller will use as much or as little to keep you moving at the same speed, pedalling. An algorithm works out how much power so that you have to pedal a fair bit at assist level 1 and much less at assist level 5. The pedal assist algorithm from Lishui is good but not as natural and does not give sharp responses like you would get with a the throttle or a torque sensor system. You can feel it when changing assist level. It ramps up the power until it detects a speed increase, then reduces the power to maintain your speed. It takes about a second to work out the sustain current. After that, you wouldn't know you ride a bike without torque sensor.
