The Alpha One is fully compatible with all rim brake IA models. Note that on the IA4, IA3, IA2, IA1, or IA FRD, the top front fairing will need to be modified to fit. This usually means trimming off the bolt tabs and finding alternative means of securing it to the headtube/stem. The Alpha One does fit on disc brake versions of the Felt IA, however the hydraulic brake cable routing has caused some issues during installation. The front fairings will once again need to be modified to fit the profile of the Alpha One's stem.