The Extype 2 piece Co-Moly crankset is designed to fit External bearing bottom brackets [The BB is not included, the Extype fits Shimano, FSA, Truvative etc external type bottom brackets]. The 2 piece construction [the drive side arm is welded to the axle], means superior strength and super easy fitment.We use an oversized 22mm, hollow, Cro. mo, heat-treated axle to shave the weight and maintain the strength.Our new 4 bolt, triple, forged alloy spider comes ready fitted to the crank and is driven by tough splines, not by the conventional single drive bolt, say goodbye to any creaks, sheared bolts or ovalised sprocket drive holes. The spider locks to the splines with a lock ring and spring clip. Spiders are available in 5 arm compact drive, or fit DMR Splinedrive chain discs [38t, 36t, 28t].Black or Chrome170mm or 175mm