SHIMANO BB-ES51 Octalink V2 Bottom Bracket Review Posted by GiantPandaisy June 12, 2018 in Drivetrain Components Octalink V2 compatible Labyrinth seals keep contamination out of bearings Standard BSA threading 22mm hollow spindle Shimano Reference Number: BB-ES51 the smooth sealed bearings of the Shimano BB-ES51 will keep you pedaling smoothly for miles. Cycling Outdoor Recreation Parts & Components SHIMANO Sports & Outdoors