The bottom bracket is an essential intermediate element between the bicycle frame and the bottom bracket. Its function is to fix the bottom bracket to the bicycle frame while ensuring a 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 English BSA / BSC thread, the current standard, the French 35 x 1mm thread, the Italian thread and the Swiss thread.