Asymmetrical coupling profile between a central axle of a bottom bracket of a bicycle transmission and a pedal crank

摘要

The coupling profile (30; 30') comprises, in a plane transversal to the axis (X) of the bottom bracket, outer arcs (CD; CD') belonging to the same outer circumference (31) of the coupling, each of such outer arcs (CD; CD') being flanked and filleted on one side to a power transmission line (AC) and on the opposite side to an idle line (DA; D'A). The power transmission line (AC) and the idle line (DA; D'A) are asymmetrical to each other with respect to the outer arc (CD; CD') that separates them.