Ritchey Classic Zero Seatpost - 31.6 400mm 0mm Offset SilverRitchey Classic Zero Seatpost 31. 6 400mm 0mm Offset Silver. Classic seat post provides a class leading balance between strength weight and adjustability. The clamp design reduces stress on lightweight rails and wont bottom out and the bolts are oriented to the axis of the rails for greatest contact area with the saddle. The Classic also features Ritcheys Classic high polish silver finish. Low profile clamp reduces stress on lightweight rails and wont