Abstract: An improved seat mechanism for use in supporting the operator of a bicycle, exercise machine, moped, motorcycle or similar device is described, having seat extensions pivotally connected to the sides of the rear seating area. The seat extensions are normally positioned at a downward angle when the seat is unloaded to facilitate easy mounting of the device and, upon mounting, the seat extensions automatically rotate upward to a substantially horizontal position adjacent the rear seating area of the seat to provide increased seating area and support for the operator, while at the same time easing the mounting/dismounting of the seat.