Abstract: A frame including a main tube having a first end and a second end, a head tube connected to the first end, a pedal assembly mechanically connected to the main tube, wherein the pedal assembly forms a pedal circle, and a seat tube connected to the main tube, the seat tube configured to support a saddle, wherein the saddle is configured to slide along the seat tube in a plurality of intermediate positions between a fully retracted position and a fully extended position.