For the sake of simplicity and for this discussion, lets say that there are two type of bike users. The first type has fit strong legs and uses the electric motor to supplement his power. The second type is less fitter and wants the motor to do most of the work. The first fitter type often runs into mechanical problems like the sprag clutch bearings, which mainly carry the riders mechanical pedal power. The second type who rely mainly on the motor, seem to run into problems like the motor/controller overheating. Its interesting that the sprag problems is reported more on the German forum than on most of the other forums. Perhaps they pedal more??