Lightweight Hollowtech Ii 105 11-Speed Chainset Innovative Hollowtech Forged & Anodised Aluminium Crank Arms Utilise A Hollow Design That Minimises Flex & Keeps The Weight Low The Chainring Teeth Have Been Developed To Work In Conjunction With Hg-X 11-Speed Chains For Increased Contact To Provide Greater Efficiency & enhanced Power Transfer Hollowtech Ii Allows The Bottom Bracket Bearings To Be Spaced Wider Apart, Enabling The Use Of Larger Bearings & An Increased Axle Diameter Can Be Used With Shimano External Or Press-Fit Bottom Brackets The System Allows For Easier Installation, Adjustment, & Maintenance Lightweight Anodised Sg-X Aluminium Chainrings For Smooth & Precise Shifting