Wolf Tooth T47 Internal Bottom Brackets are engineered to be smooth, durable, lightweight, fast, and user-serviceable. Our ground-up design features custom bearings, seals, bushings, and cups, which eliminate creaking and balance best-in-class weather sealing with optimized bearing radial compression, alignment, and preload for low drag. Wolf Tooth bottom brackets are machined at Wolf Tooth HQ in Minnesota, USA. The bearings in Wolf Tooth Bottom Brackets feature a custom design. The balls and race are made from a hardened chrome bearing steel. This has a higher surface hardness than stainless, which improves the durability of bearing races and reduces spinning resistance and noise. An ACOSUR ZNA coating has also been applied to the race to provide corrosion resistance that is equal to or better than stainless steel after a 500-hour saltwater test. Bearing material paired with an extensive sealing system and the elimination of metal-on-metal contact means Wolf Tooth Bottom Brackets have superior performance in all conditions. - Compatible with 24, 29 DUB, and 30mm spindle cranksets - Adjustable-width sleeve fits 85.5mm - 92mm T47 Internal bottom bracket shells - Best-in-class weather sealing protects bearings from water, mud, debris - Custom Polymer spindle bushings eliminate creaking - Installation and removal with standard 52-16 spline tool - Engineered, machined, and assembled at Wolf Tooth HQ in Minnesota, USA Bottom brackets ship with the following shell and spindle spacers: - 2x2.5mm shell spacers - 24mm spindle - 2x 0.5mm, 2x 1mm, 2mm, 3mm, 5mm spindle spacers - 29mm spindle - 2x 0.5mm, 2x 1mm, 3mm, 5mm, 7.5mm spindle spacers - 30mm spindle -2x 0.5mm, 2x 1mm, 2mm, 3mm, 5mm spindle spacers Compatibility - 85.5 - 92mm width T47 Internal Bottom Bracket Shells - Included adjustable-width internal sleeve fits 85.5mm - 92mm width T47 Internal bottom bracket shells