The Park Tool BBT-179 Steel Bottom Bracket Tool is a precision-machined 4140 steel workshop tool for removal and installation of threaded bottom brackets with 12-notch tool fittings in the 4547mm major diameter range. The BBT-179 fits fittings with a major diameter of 4547mm and a minor diameter of 44mm covering SRAM BSA DUB Race Face Cinch Rotor BSA30 Zipp Vuma and Hawk Racing BB3086 among others a compatibility set that spans current performance road gravel and mountain drivetrain platforms. The extra-deep body clears extra-wide spindles and low-profile walls at the engagement point reach recessed lockrings that shallower tools miss. Three drive options 3/8″ drive 1″ hex and 36mm wrench flats address even the most seized bottom bracket cups and integrated threads in the tool body accept the Park Tool BBT-RS Bottom Bracket Tool Retaining System or GPS-1 Guide Pins (each sold separately) for improved alignment and stability during service.