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 45×45 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