What are Interlok Spacers, and do I have to use Interlok Spacers with Cane Creek headsets?

Are they necessary? No, but there’s a few good reasons why you might want to use them: Our patented Interlok spacer design provides solid interface between the top cover and spacer stack, meaning they “nest” together and into the top of the bearing cover, which helps minimize shifting under load while riding; and our “Scalloped” spacers shave 25% in weight off a standard alloy spacer stack. Where you want your stem height to be will determine how many and what size spacers you may need.