Full Speed Ahead 8420ST Power Drive Bottom Bracket - English A Replacement Bottom Bracket Replacement bottom bracket for FSA's Power Drive splined cranksets. The stiff forged hollow chromoly spindle is supported by a pair of sealed industrial cartridge bearings. Additional weather protection comes from double "Snap" seals. Features Forged hollow SCM4130 chromo spindle Industrial 6002KRS cartridge sealed bearings with oversized 3/16" diameter balls Double "snap" seals for water and dirt protection | Fsa | Full Speed Ahead 8420St Power Drive Bottom Bracket - English 73X113Mm