Cane Creek 40 Series Conversion Crown Race 52/30. Use this to convert your straight steerer fork in a modern tapered head tube frame. The Cane Creek 40 Series Conversion Crown Race 52/30 allows you to run a 1-1/8" straight fork with a 30mm crown race seat in any Cane Creek headset with a 1.5" lower bearing. The Cane Creek 40 Series Conversion Crown Race 52/30 is constructed of durable steel and features a low friction seal that runs light against the face of the lower cup to keep bearings from being contaminated with debris from the the front wheel.SPECIFICATIONS:COMPLETE/TOP/BOTTOM: BottomCrown Race Seat Diameter: 30mmMaterial: SteelMFG. PART NO. BAA0009SS.H.I.S.: 52/30Steer Tube Diameter: 1.5'' to 1-1/8''UPC: 840226101651