Suppose you have a frame with a 1 18 to 1. 5 tapered head tube and a fork with a 1 18 straight steerer tube. It's not a problem, you simply need this 110 Series 5230 Conversion Crown Race to adapt the fork's 30mm o. d. crown race seat to the 1. 5 lower bearing in your Cane Creek Headset. While we also sell the 40 Series version and it's exactly the same dimensions as this one, this 110 Series Crown race is their finest offering. It's made of stainless steel and features a Dual Seal to mate with the lower cup to keep out any gunk that could hamper your headset function.