A central frame assembly for a passenger seat of a vehicle includes a spreader member (201) and a lower frame member (101) comprising at least one clamp member (121) for securing the lower frame member (101) relative to the spreader member (201). The lower frame member (101) may include a vertical portion (102) with a forward lower attachment portion (102.1) and an aft portion (103) with an aft lower attachment portion (103.1). The spreader member (201) and the lower frame member (101) may be aligned such that a centerline of the spreader member (201) and a centerline of the lower frame member (101) are approximately coplanar.