High performance 9 speed cassettehyperglide sprockets have a computer designed tooth configuration with contoured shift gates44 resulting in a crisp smooth shift even under loadclose ratio gearing allows a more efficient use of energy through finer cadence controlsix largest sprockets are mounted on a lightweight alloy carrier to reduce weight and increase rigiditysprockets are cut away and drilled to further reduce weight without reducing rigiditychrome plated finish offers hard wearing resi