Lightweight Hollow Tech II 105 10-speed chainset Innovative Hollow Tech 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 the CN-5701 chains for increased contact to provide greater efficiency & enhanced power transfer Hollow Tech II allows the bottom bracket bearings to be spaced wider apart (outboard from the frame) enabling the use of larger bearings & an increased axle diameter The system allows for easier installation adjustment & maintenance Lightweight anodised SG-X aluminium chainrings for smooth & precise shifting For use with ST-5700 ST-6700 or ST-7900