The Hollow Tech II 10-speed CX70 cyclo-cross chainset offers an ideal balance of light weight & stiffness making it the perfect choice for both enthusiast & competitive riders Machined alloy outer chainring is both rigidity & lightweight The chainring teeth have been developed to work in conjunction with the CN7901 & CN6701 10-speed directional HG chains for increased contact to provide greater efficiency & enhanced power transfer Industry leading Hollow Tech II cold forged hollow crank arms have been evolved to increase rigidity reduce weight & improve strength A wide range of crank arm lengths are available to meet the needs of all riders Hollow Tech II integrated bottom bracket uses a wider bearing placement & larger axle diameter for increased stiffness & efficiency Hollow Tech II integrated bottom bracket seal design has minimal bearing interface ensuring smooth rolling & increased durability 46 / 36T chainrings using 110 mm bolt circle diameter