Full Speed Ahead FSA Orbit C-40 Tapered Integrated Bicycle Headset - 121-0514 1-1/8" upper, 1.5" bottom 45deg/45deg upper bearing - 1-1/8 36deg/45deg lower bearing - 1.5 For tapered fork steerer 1.5" to 1-1/8" Alloy 8mm top cover