fast end furious :) used only 50mis Cervelo r5 used with seat post and 3D rotor + Road Cranks Cervelo R Series is engineered to optimize strength, stiffness and comfort while offering low weight in every situation. An R Series bicycle offers the best of our Project California-developed lightweight Squoval three tube shapes, which have been engineered to offer premium ride quality with ultra-thin seat stays developed to increase vertical compliance and vibration absorption.