It is essential to take steps to protect the paintwork on the bottom bracket shell from damage by the chain.

The down tube connects the head tube to the bottom bracket shell.

There may be a small brace that connects the chain stays in front of the rear wheel and behind the bottom bracket shell.

The bottom bracket shell is large to accommodate removal of this S-shaped crank.

Bearing cups are pressed into the bottom bracket shell.

The spindle is made longer, and the bearings sit outside the bottom bracket shell.

Bicycle frames utilizing pressed bearing standards do not have any threads inside the bottom bracket shell.

Some downhill bikes even use a 83 mm bottom bracket shell.

Therefore, Phil Wood cartridges can be fitted to just about any type of bottom bracket shell.

As a result the inside diameter of the bottom bracket shell is increased to 42mm.