It's easy to forget about your bottom bracket. It's hidden away in the frame, all but invisible. The only time it makes its presence felt is when it starts to tire of the endless rotations and decides to experiment with creaks, grinds, rattles and movement in hitherto unexplored directions. None of this is good. Once upon a time, all bottom brackets were adjustable cup-and-cone affairs that could be stripped, cleaned, regreased, refitted and readjusted. All of which was as much of a faff as it sounds. These days most BBs are fit-and-forget affairs, until they die at which point you chuck 'em and put another one in. Here's how...

We're looking at Shimano bottom brackets here, the most common type. Most others work on the same principes, although some exotic ones have their own installation nuances - if you've got one of those, refer to the instructions that came with it.

This is a pretty messy job. In addition, have a couple of rags to hand for wiping things with, otherwise your trousers are never going to be the same again.

Bottom Bracket
bb 1

 

Bottom Bracket
bb 2

 

 

 

 

Bottom Bracket
bb3
Bottom Bracket
bb 4
Bottom Bracket
bb 5
Bottom Bracket
bb 6
Bottom Bracket
bb 7

 

 

Bottom Bracket
bb8
Bottom Bracket
bb 9
Bottom Bracket
bb 10
Bottom Bracket
bb 11