Abstract: A structure for frames for bicycles, wheelchairs, and other vehicles, as well as components thereof and other devices requiring a strong, lightweight frame shell. The preferred frame structure is constructed from plastic molded partial shells that are assembled into shells (such as tubing) that comprises the frame. The partial shells have protrusions and receptacles on the joining faces of their skins that are used to join the partial shells together to form the assembled shell. This results in a lightweight, durable and aesthetically pleasing frame. In an alternative embodiment, the partial shells have protrusions and receptacles within their interiors for additional strength. Additional attachment mechanisms such as screws, bolts, nails, clips or rivets may be used for reinforcement of the partial shells. A method for manufacturing the frame is also disclosed.