Promax CF-2 Crankset - 160mm 24mm Spindle 2-Piece 68mm English BB Included SilverPromax CF 2 Crankset 160mm 24mm Spindle 2 Piece 68mm English BB Included Silver. Promax CF 2 cranks deliver a great combination of stiffness durability and weight savings. Cold forged from 6061 T6 aluminum to be strong yet lightweight CF 2 cranks feature a two piece design that incorporates a beefy 24 millimeter spindle permanently fitted into the drive side arm. Cold forged 6061 T6 aluminum arms 104mm BCD Includes a sealed 68mm English bottom bracket