A high performance chainset from the classic atb group using the most advanced 10 speed dyna sys chainringsforged hollowtech ii aluminium cranks offer unrivalled strength to weight ratiolightweight construction with external super smooth bottom bracket bearings for efficient usedrilled steel and carbon composite construction middle ring combined with a thicker aluminium double anodized 42 tooth and plated aluminium 24 tooth ring for excellent rigidity and durabilityclose ratio gear combination