Posted in Cycle
Shimano threaded bottom bracket image

Bottom brackets explained

The bottom bracket is a component that is housed in the bottom bracket shell of a bike frame. The purpose of the bottom bracket is to connect the chainset to the frame, this allows the chainset to rotate smoothly. As technology evolves bottom brackets have too, and can be very minimalist, typically bottom brackets are now cups/bearings only, with the axle/spindle integrated into the chainset.

Why are they good?

Modern day bottom brackets are normally a case of "fit and forget"; being sealed units they are maintenance free. You replace the bottom bracket once the bearings are no longer turning smoothly or develop a rocking movement from side to side known as play. Gone are the days of patiently adjusting a bottom bracket with two spanners working in opposite directions to get optimal smoothness.
New larger bottom bracket shells and outboard bearings have allowed larger axles/spindles on chainsets. This has allowed a significant increase in lateral frame stiffness in this critical area, improving the power transfer through the frame.

How do I choose?

Each bottom bracket variation has benefits over its competition if you read the technical data and findings, and with over ten varieties it can appear complicated at first. Your bottom bracket shell type dictates what options you have available for a bottom bracket, and at Wiggle we stock bottom brackets to suit all bikes. The most common types of bottom bracket are traditional/square taper, external cup bearings and press fit bearings.Generally the higher you go in a component hierarchy the better quality the bearings and quality of materials becomes, this is reflected in pricing.