The shimano claris 2450 compact 4634 octalink chainset is a great valve cyclocross chainset with lightweight crankarms and hard wearing steel sg x chainrings the chainrings feature strategically placed chain pick up pins and tooth profiles to ensure fast and positive shifting and are compatible with shimano 8 speed hg chains the crankarms are designed for shimano octalink bottom brackets which a stiffer option to a square tapered bottom bracket