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 45-47mm major diameter range. The BBT-179 fits fittings with a major diameter of 45-47mm 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.Machined from 4140 steel for heavy-duty workshop useFits 12-notch threaded bottom bracket tool fittings with a major diameter of 45-47mm and a minor diameter of 44mmCompatible with SRAM BSA DUB Race Face Cinch Rotor BSA30 Zipp Vuma and Hawk Racing BB3086Extra-deep body accommodates extra-wide spindlesLow-profile walls at the point of engagement reach recessed lockringsThree drive options: 3/8" drive fitting 1" hex fitting and 36mm wrench flatsOuter diameter at point of engagement: 50.04mm (1.97")Internal clearance: 42mm (1.654") depth x 30.44mm (1.198") diameterIntegrated threads accept Park Tool BBT-RS or GPS-1 Guide Pins for added stability (each sold separately)Not rated for use with impact drivers