Promax EX-1 Bottom Bracket

EX-1 External bottom brackets feature cold-forged and CNC-machined alloy cups, dual-labyrinth bearing covers and precision sealed bearings. They are the perfect match to Promax CF-2 and HF-2 cranks and ultimate upgrade to the budget BBs sold with most crank sets.

Available to fit all 24-millimeter bottom bracket spindles and frames with 68 or 73 x BC1.37” bottom bracket shells.