Abstract: A recumbent trike includes a frame constructed of metal or carbon fiber tubes that are interconnected by metal fittings. The frame includes a pair of main tubes extending front to rear that provide a very stiff and lightweight structure that is relatively stiff when subject to side loads generated in turns, yet relatively flexible when subject to vertical loads caused by bumps in a road surface, thereby enhancing rider enjoyment. A seat is adjustably supported on the main tubes, to provide for fore-aft adjustment to accommodate riders having a wide range of heights. The back support portion of the seat is also adjustably connected to the frame to provide for greater or smaller recline angle. The drive chain extends through one of the main tubes of the frame, such that external chain guides or supports are not required.