I have a Bafang BBS02 installed on my Cannondale Quick 4 hybrid with 9-speed cassette. It works really well, EXCEPT the the shifter cannot raise the chain to the largest (lowest gear) sprocket. The drive sprocket is the standard 44-tooth one that was supplied with motor. It is not a great hinderance unless I ride without the motor where I want to use the lowest gear.
Is there a solution for this, such as a concave 44-tooth drive sprocket that would allow the shifter/chain to travel the the whole range of 9 gears at the back?