X.P.S.S. (eXtreme Performance Shifting System) is the acronym that denotes the most effective and efficient system ever, with the absolute best shifting speed and precision even under load. The Chorus crankset with carbon fibre is the ideal partner for any competition. Specifications: Length: 170, 172.5, 175 mm Combinations: 39/53 - 36/52 - 34/50 Weight: 683g Features: Ultra-Torque Axle - Pressure on the pedals is transmitted effciently without any power loss. New Chainrings - Sophisticated mechanical features on the parts that move the chain up and down guarantee maximum effciency during shifting. Differentiated number of pins depending on the chainring combination - Constantly optimum engagement of the chain. Maximum shifting effciency. Hollow crank and spider arms with Ultra-hollow technology - Reduced weight of stress – free sections, improved crank set weight to stiffness ratio. Double standardized bolt circle diameter on all combinations - Maximum stiffness and lightness thanks to extension of the carbon fber crank close to the chainrings with 112 mm for the small bolt circle diameter and 145 mm for the large one. Intergrated crank/chainring mounting system - reduced weight – easy maintenance.