Wolf Tooth MARKZERO (MK0) Bottom Brackets deliver high performance through aggressive machining, custom ceramic bearings, and intricately designed race sealing built to exacting specifications. These components save watts while proving durable enough for intense off-road racing and inclement conditions, and are fully serviceable. MK0 components are proudly machined at Wolf Tooth HQ in Minnesota, USA. The MK0 features silicon nitride ceramic bearings with custom race sealing for flawless performance against the elements and enhanced speed. Custom polymer spindle bushings separate the bearing inner race and crank spindle to eliminate metal-on-metal contact, which is the leading cause of bottom bracket creaks. The bushings also enhance bearing longevity by providing an interface to the bearing gutter seal for maximum weatherproofing. The bottom bracket is aggressively machined to be lighter than the competition while offering superior speed and performance in all conditions. Construction includes 6061-T6 aluminum cups and AISI 52100 chrome bearing steel races hardened to Rc 60-65 with ACOSUR-ZNA corrosion resistant coating.