How to replace an external bottom bracket

The best way to replace an external bottom bracket - with walkthrough video

Changing a bottom bracket may at first seem like a dark art, best left to wizard-like mechanics found hiding only in the most spooky and dingy of workshops. However, with a little investment in the right tools, changing an external bottom bracket is a very simple task. No dark magic required.


Systems such as Shimano’s Hollowtech II use external bottom brackets that place the bearings on the outboard of the bottom bracket shell. Compared to traditional, internal bottom brackets, this allows for the use of larger bearings, which can help improve the longevity of the bottom bracket.

Despite this, external bottom brackets do need replacing once play develops in the bearings and in this step-by-step video walkthrough below, BikeRadar’s James Tennant explains how to replace your worn out bottom bracket cups.

Find out how to replace your external bottom bracket in our walkthrough video

Are you a serial bottom bracket destroyer? Perhaps it’s time for an upgrade. Check out our recommendations here.