Hollowtech-II (HT2): integrated bottom bracket spindle with right crank for increased rigidity while left arm mounts to splined spindle 7075 aluminum HyperGlide chainrings with shift ramps and pins 5750: compact @ 805g, 5600: double @ 825g, 5603: triple @ 910g *Outboard, alloy bottom bracket bearing cups sold separately: use SH-14303 (68mm English) or SH-14304 (70mm Italian)