Bottom brackets are the part of your bike that connects the cranks to the cycle and helps in the rotation of its arm. There are three common types of bottom brackets widths: 68 mm, 70 mm, and 73 mm. It is also available in many shapes and sizes like ISO square tapers, new external cup system, BB30 system, and much more. Every style uses a different mechanism to perform its function, and our bottom brackets collection from brands like BBB and Colony has it all. Also check out our collection of Chainrings and Cables.