Upgrade your stock bottom bracket. Enduro bottom brackets are designed to spin more efficiently and for longer. Enduro's ABEC 5 is the next performance step up from the popular ABEC 3 range. By using military level, high precision HRC-64 hardended Grade 5 Chromium Steel Balls, and 52100 High-Carbon Chromium-Alloy mirror polished races. This combination allows Enduro's ABEC 5 bearings to use tolerances twice as tight as ABEC 3, and operate without any noise. The Graphite/Nylon ball retainers allow virtually frictionless movement and provide constant lubrication to maximise the life of the bearing. Key Features: Fits BB86 frames - 41mm diameter with a shell width from 86.5mmFits chainsets with 30mm axleLightweight, durable Delrin cupsDurable ABEC 5 Bearings71.29g