Trek has decided to join the Bosch mid-drive family with a new model that is a hard-tail called the
Powerfly+9.
One difference that stands out is the unusually small chainring. It looks like it may be a BB-shaft inside a freewheel adapter. This would allow the rear wheel to be powered without adding any pedaling. Europe and Asia are dominated by
pedelec systems, and this is where you must pedal for the controller to add power to the chain.
If this truly is a freewheeling Bottom-Bracket (BB), then this bike can be powered without pedaling, which is popular in North America. - electricbike.com