Wolf Tooth MK0 BSA Bottom Bracket - For Shimano Ceramic Speed, Creak-Free. Serviceable for Life. Creaking bottom brackets are a rolling distraction. The MK0 BSA solves that problem at its root with custom polymer spindle bushings that sit between the bearing inner race and the crank spindle. Those bushings eliminate metal-on-metal contact, which is the leading cause of bottom bracket creaks. Add silicon nitride ceramic bearings with custom race sealing and the result is a BB that spins clean and quiet from the first pedal stroke. The sealing system is designed to balance low drag with all-conditions performance, layering a spindle o-ring, gutter seals, light inner and outer bearing race seals, shell o-rings, and a labyrinth-style end cap so mud and water stay out of the races. The adjustable-width design covers both 68mm and 73mm BSA shells with a single unit, and install requires no proprietary tools. Bearing replacement can be done at home, and Wolf Tooth provides video and text service guides to walk you through it. When a ceramic BB typically sacrifices durability for low drag, the MK0 is the option that doesn't make you choose. Silicon nitride ceramic bearings pair ceramic speed with best-in-class sealing, addressing the common ceramic BB weakness of low durability Custom polymer spindle bushings separate the bearing inner race and crank spindle to prevent metal-on-metal contact and interface with the bearing gutter seal for maximum weatherproofing Adjustable-width shell fits 68mm to 73mm BSA shells in one unit, with 83mm DH and 100mm Fat Bike sleeves available separately Standard spline installation uses standard 44-16 spline tools, so no proprietary tooling is required Machined in Minnesota, USA: designed, machined, and assembled at Wolf Tooth HQ with aggressive CNC work to keep weight low without sacrificing shell integrity SPECIFICATIONSSpindle Size24mm29mm30mm Weight76g82g77g | Wolf Tooth Components | Mk0 Bsa Bottom Bracket - For Shimano | Shadow Gray | 24Mm