Task Summary
Facing or reaming the Bottom Bracket shell is necessary for the installation of outboard BB bearing cups. If the BB shell is not completely smooth the bearings will wear out much more quickly.Facing is also relevant to other parts of the bicycle such as facing or reaming out a headtube, or reaming a fork’s crown race. For the purposes of this section we shall look at BBs only.
Tools
WORKSHOP TIP: All Facing/reaming tools will require different stages to set up and use. It is best to consult the manufacturer manual for a step by step guide to your unit.
A common BB facing/reaming tool consists of the handle - which provides grip for the mechanic and connects to the threaded bar – which allows adjustment and connects the cutter and locating hardware to the handle. The cutter cuts metal away from the shell in small slivers and the locating bit and spring ensure the tool stays straight in the shell by threading in and using the spring tension to keep the central pin straight. You will also need some cutting oil.
