The bottom bracket is an essential intermediate element between the bicycle frame and the crankset. Its function is to fix the bottom bracket to the bicycle frame while ensuring perfect rotation of the bottom bracket. The bottom bracket consists of 2 cups, 2 bearings and an axle. There are different threads for bottom brackets: the British BSA / BSC thread, the current standard, the French 35 x 1mm thread, the Italian thread and the Swiss thread.