RTCL8_z__z_MJ RT_h_CL8_z__z_ Ice Tech FREEZA rotor with internal magnet lockring, 18_z_ mm Shimano STEPS Silver _fsla_ Black Centre Lock _h_ 18_z_ mm 455_z_17_z_3_z_9596 Parts 455_z_17_z_3_z_9596 Shimano Latest Series Shimano Steps RTCL8_z__z_ RTMT8_z__z