Abstract: A power assist apparatus is to be mounted in a straddling position about the rear wheel of a bicycle. The power assist apparatus includes a housing with this housing to be mounted on a support bracket assembly which is fixedly mounted on the frame of the bicycle. The support bracket assembly includes pins which are to connect with the housing of the power assist apparatus. The latching assembly is to connect between the frame of the bicycle and the housing of the power assist apparatus with this latching assembly to be movable between a latched position and an unlatched position.