The Park Tool BBT-135-12 Steel Bottom Bracket Tool is a heavy-duty workshop tool machined from precision 4140 steel for removal and installation of threaded bottom brackets with 12-notch tool fittings. The BBT-135-12 fits 12-notch fittings with a major diameter of 48–50mm and a minor diameter of 46.3mm including Praxis Works M30 bottom brackets — a standard found across a wide range of contemporary road and gravel drivetrains. The extra-deep body handles extra-wide spindles and low-profile walls at the engagement point seat into recessed lockrings that standard-depth tools miss. Three drive options — 3/8″ drive 1″ hex and 36mm wrench flats — handle even heavily seized 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 stability during service.
Machined from 4140 steel for heavy-duty workshop use
Fits 12-notch threaded bottom bracket tool fittings with a major diameter of 48–50mm and a minor diameter of 46.3mm
Compatible with Praxis Works M30 bottom brackets
Extra-deep body accommodates extra-wide spindles
Low-profile walls at the point of engagement reach recessed lockrings
Three drive options: 3/8″ drive fitting 1″ hex fitting and 36mm wrench flats
Outer diameter at point of engagement: 57.5mm (2.264″)
Internal clearance: 42mm (1.654″) depth x 30.44mm (1.198″) diameter
Integrated threads accept Park Tool BBT-RS or GPS-1 Guide Pins for added stability (each sold separately)
Not rated for use with impact drivers
