Abstract: A bicycle of the "mountain bike" type having two aligned foldable joints in the frame, a folding handlebar assembly and a foldable pedal. Each of the frame joints is mounted in a gap in a tubular frame member and includes two disks disposed flushly against the ends of the tubular members with smaller plugs fast in the members, and two hinge leaves extending across the gap longitudinally of the frame. A rivet on one side of the joint joins two ears on the leaves to form the hinge axis, and a headed fastener with a hexagonal socket is recessed into the thickened central portion of the upper leaf and threaded into the lower leaf to clamp the leaves together. Interlocking ribs between two ears on the other side of the joint prevent relative pivoting movement when the leaves are clamped together. The handlebar assembly has upper and lower tubular adjustment sections for both upward and forward adjustment of the handlebar, and an angled hinge between these sections.