The bottom bracket is a very important part of a bicycle. It is placed into the bottom side of the frame and is one of the parts responsible for the bike traction system since it supports the power while pedalling. It is where you connect the cranks, and afterwards the chainring and pedals. This English, or BSA, bottom bracket belongs to the JIS standard, it is 103 millimetres long, it has sealed bearings with steel shaft and cups. BSA or English bottom brackets are generally used for modern bikes. This is the bottom bracket of choice if the crankset of your bike tells you to combine it with a 103mm bottom bracket. This way you\'ll ensure the perfect chain alignment of your bike.