Shimano sora double 3550 9 speed chainset 2 piece design double ring 9 speed chainset from the excellent value sora range sg x chainrings feature strategically placed chain pick up pins and tooth profiles to ensure fast and positive shifting 2 piece design allows the bottom bracket bearings to be spaced wider apart outboard the frame enabling the use of larger bearings and an increased axle diameter there is also the benefit of easier installation adjustment and maintenance compatible with