A conventional bicycle of the type having a frame with an upper bar between an upright seat-supporting member and a steering fork bearing assembly is converted to a high-ride bicycle by a bifurcated seat extension having a housing for a pedal sprocket bearing assembly on the end of one branch which extends forwardly along the upper bar. Clamping means secures the forwardly extending branch to the upper bar. A downwardly extending branch is clamped in the bicycle frame in the place of the seat, and the seat is clamped in place at the upper end of the seat extension.

A tricycle which is capable of being converted either to a traditional high position in which a rider is seated relatively high on the frame, or to a low slung position in which the frame is inverted so that a rider is seated relatively low on the frame. To invert the frame, the a front fork and handlebar are removable from the head tube of the tricycle and invertible relative to the frame and the seat is adjustable between a high and low position corresponding to the high and low slung tricycle positions. A rear deck is attached to a rear portion of the main tube and is tubular in shape so that it fully and protects encloses the rear axle of the tricycle in both the high and the low frame positions. A seat is mounted on the frame and is capable of forward and rearward adjustment as well as upward and downward adjustment. A dumpster is pivotally attachable to the frame adjacent the rear deck and includes notches that form an easily releaseable snap fit with the rear axle of the tricycle, and a channel formed in a front wall shaped to form a releasable snap fit with the rear portion of the main tube. The rear deck and pedals of the tricycle include upwardly extending flanges to prevent the feet of a rider on the tricycle from sliding sidewardly to contact the rear wheels, pedal crank supporting the pedals, or the front wheel.