Fsa orbit c 40 acb 15 headset no 42acbtapered headsets are a combination of the other styles usually a tapered steerer tube will have a 118 or 15 lower diameter and a 118 upper diameter the headsets for these frames forks can be any combination of traditional internal or integrated headsets it is very important to accurately measure the inner diameter of the headtube top and bottom to narrow down the headset model needed in some cases tapered headtubes can be used with a str