Threaded BSA Technical Info

The frame's bottom bracket has threads cut in to the shell. Typically threads are BSA (1.37" x 24tpi), Italian (36 x 24tpi) or French (35mm x 1). Most of the current bottom brackets available from Shimano, SRAM, FSA and Campagnolo use external bearing cups. Wheels Mfg offers an external bearing cup bottom bracket for both road and mtb bottom bracket shells.

  • Shell width: 68mm (road) or 73mm (mountain)
  • Shell threads: BSA 1.37 in x 24 TPI
  • Drive side cup is left-hand thread
  • Non-drive side cup is right-hand thread

Threaded Exploded View

Threaded Tech Links

Road

MTB