Wolf Tooth T47 Internal bottom Brackets are engineered to be smooth, durable, lightweight, fast, and user-serviceable. Their 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. The Wolf Tooth Bottom Bracket bearings feature custom designed balls and races that are made from a hardened chrome bearing steel which has a higher surface hardness than stainless to improve the durability, reduce 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 deliver superior performance in all conditions. Wolf Tooth bottom brackets are designed, engineered, machined and assembled in-house at Wolf Tooth HQ in Minnesota, USA.Bottom bracket also includeds: (2) 2.5mm shell spacers, (2) 0.5mm spindle spacers, (2) 1mm spindle spacers, (1) 2mm spindle spacer, (1) 3mm spindle spacer, and (1) 5mm spindle spacerBest-in-class sealing achieved by grouping a spindle o-ring, seals on the bearing/bushing gutter, inner and outer low contact bearing seals, shell o-rings, and a labyrinth-style end cap to ensure your bottom bracket will run smoothly no matter what conditions you ride inCustom bushings separate the bearing inner race and crank spindle to eliminate metal-on-metal contact, the leading cause of bottom bracket creaks, while also aiding in bearing longevity with an interface to the bearing gutter seal for maximum weatherproofingCustom AlSl 52100 chrome bearing steel hardened to Rc 61-66 reduces friction for smooth pedaling with ZNA corrosion-resistant coatingAdjustable-width design allows the same shell to be used for 85.5mm - 92mm width T47 Internal Bottom BracketsEasy installation and removal using a standard spline 52-16 bottom bracket tool (Sold separately)Item SpecificationsBB Shell Width (mm)86BB Shell Width (mm)92BB/Frame InterfaceT47Bottom Bracket Shell I.D.47Defined ColorBlackSpindle Interface Type386 EVOSpindle Interface Type392 EVOSpindle Interface TypeRaceFace/Easton CINCHWeight91 Wolf Tooth T47 Internal Bottom Brackets Bottom Brackets UPC: 810159401463