The shimano sora fc 3550 sora 9 speed compact chainset is the latest and greatest addition to the sora range with several key design features the sora 3550 is the pinnacle of ease of use and performance in a 9 speed chainset the unique design of the sora includes a 2 piece design double ring offering you the chance to use larger bearings and an increased axle diameter thanks to the space for wider bottom bracket bearings with an aluminiumsteel build material the sora is super lig