Shimano Dura Ace 7700 Octalink Bottom Bracket - 109mm From £99.99

I don't know why Shimano calls this a "cartridge unit." It is not. It is in fact made up of two sets of loose bearings, ball bearings for the side to side motion, and roller bearings to bear the load. This is as good as it gets, and this bottom bracket is light as well. Shimano still sells this for track use, although it does fit their old road cranks.