Rotor BSA30 - 68/73mm - Steel - Black In an ever-growing sea on bottom brackets standards it is becoming increasingly frustrating to find the right bottom brackets for your favorite bikes. Luckily Rotor has you covered. The Rotor BSA30 - 68/73mm easily accommodates to English threaded bottom brackets. The Rotor BSA30 Steel threaded Bottom Bracket is part of the company's UBB System, which allows far more cranks to work with basically any frame. In this case, this BB allows for the installation of a Rotor 3D30 or other 30mm axle crankset onto an English threaded bottom bracket. Specs Designed to work with BSA threaded bottom brackets and 30mm axle ROTOR cranksets aluminum alloy 7075 100% CNC-machined Silicone seals | Rotor | Bsa30 - 68/73Mm - Steel | Black | 68/73