BSA bottom bracket
BSA is a threaded standard: the bottom bracket shell has an internal thread, so the bottom bracket screws straight into the frame. You recognise a BSA frame by a shell 68 or 73 mm wide with an inner diameter of 33 mm (BSA thread).
View all BSA bottom brackets Not sure? Use the bottom bracket finder
Sizes of a BSA bottom bracket shell
68 or 73 mm
Shell width
33 mm (BSA thread)
Inner diameter
threaded
Inside of the shell
Frequently asked questions
CEMA has BSA bottom brackets for Shimano, SRAM DUB, SRAM GXP, FSA386/Rotor/Raceface 30mm and PRAXIS M30 cranksets.
Measure the bottom bracket shell: on BSA it is 68 or 73 mm wide, with an inner diameter of 33 mm (BSA thread).
A BSA shell is 68 or 73 mm wide, with an inner diameter of 33 mm (BSA thread). An ITA shell is 70 mm wide, with an inner diameter of 36 mm (ITA thread). More about ITA →
A BSA shell is 68 or 73 mm wide, with an inner diameter of 33 mm (BSA thread). A T47 Outboard shell is 68 or 73 mm wide, with an inner diameter of 46 mm (T47 thread). More about T47 Outboard →
Still not sure?
The bottom bracket finder takes you to the bottom bracket that fits your frame in a few questions.
Go to the bottom bracket finder