Shimano BB-ES300 Octalink bottom bracket – for MTB and Touring
The Shimano BB-ES300 Octalink bottom bracket with 8-speed gears fits MTB and touring cranks installed in BSA bottom brackets with 68 or 73 mm shell width. Compared to its predecessor the BB-ES25, it can save up to 25 grams of weight. This is the standard version, which is not compatible with E-Type or chain cases.