Bicycle frame

A one unit bicycle frame for a bicycle having two wheels in line, with a front steerable wheel, and having a head tube, top tube, down tube, seat tube, and a seat post for supporting a seat, and chain tubes with rear wheel lugs:

• said one unit bicycle frame having a horizontal rectangular structurally integral member located over the rear wheel and generally parallel to the ground, and having a front cross tube, a rear cross tube, and left and right longitudinal side members, the left and right side members having curved extensions curving inwardly and connected to the seat tube at a generally right angle to a longitudinal axis of the bicycle frame, with said longitudinal side members being spaced by, and connected together by said front and rear cross tubes at right angles to the longitudinal side members, and said rectangular member having a gusset plate installed on its top, secured with a fastener through holes on the periphery of the gusset plate into tabs provided with holes, said tabs located on the longitudinal side members, and said rectangular member being supported from underneath in a position parallel to the ground by left and right first downward tubes connected respectively to the front underside of the left and right longitudinal side members at a position rearward of the curved extensions and left and right second-downward tubes connected respectively to the rear underside of the left and right longitudinal side members, with the first and second downward tubes terminating at and connecting to respective left and right rear wheel lugs.