Cylindrical bicycle bottom bracket adapter for bicycle gear shift, has left- and right- sleeves connected to each other by screwing, where right sleeve is provided with right inner thread for screw connection with internal crank mechanism

摘要

The cylindrical bicycle bottom bracket adapter (10) has a left sleeve (12) and a right sleeve (14), where the sleeves are connected to each other by screwing. The right sleeve is provided with a right inner thread for a screw connection with an internal crank mechanism. The left sleeve is inserted into a non-driving side of a bottom bracket of a bicycle, while the right sleeve is inserted into a driving side of the bottom bracket. The left sleeve and the right sleeve are provided with a flange that is positioned on an outer periphery resting against an outer surface of the bottom bracket.