The Shimano SM-BBR60 bottom bracket features is designed to match the 6800/R8000 Ultegra groups and features a 25 gram weight reduction over the previous generation plus a new black-anodized finish. To achieve this considerable weight loss the external cup size is noticeably smaller thanks to smaller bearings and a reduced external diameter. The internal diameter and the width of the cups is the same so this bottom bracket will work with older Hollow Tech II road designs as well.

This design has a 41mm OD, with a 16 notch spline receiver. Park Tool offers the BBT-59.2 for this set-up, and other options are widely available. Other than the smaller cup and bearing size, the system is still Shimano's well proven Hollow Tech II design with a 24mm internal diameter and the benefits of a wider bearing platform, easy installation and serviceability. Improvements don't stop at weight reduction. New bearings and seals allow a claimed 50% reduction in friction so your cranks will spin more freely plus there is no pressing need to jump to ceramics.