ACS Maindrive integrated step down (AKA Reducer) headsets will suit mini to expert sized frames with an integrated 1-1/8″ headtube and work with forks with a 1″ steerer tube. Featuring an aluminum cap, bearing cover and crown race with super-smooth rolling, precision 4545 bearings.

– Suitable for 1-1/8″ integrated (41.8mm) frames with 1″ forks

– Crown Race: 26

– S.H.I.S Lower: IS42

– S.H.I.S Upper: IS42

– S.H.I.S. Stem Clamp Diameter: 25.4 Threadless