An attachment (4, 30, 40) for connecting a first bicycle (1) to at least one second bicycle (2), the bicycles (1, 2) being connected in the direction of motion, and the attachment (4, 30, 40) being rotatably connected to at least one bicycle (1, 2) and extending in a substantially fixed length transversally to the direction of motion, between its respective mounting points (8, 12, 34, 42, 44, 46) on the first bicycle (1) and the second bicycle (2), respectively.