Suppose you have a frame with a 1-1/8" to 1.5" tapered head tube and a fork with a 1-1/8" straight steerer tube. It's not a problem, you simply need this 110-Series 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.