A support for removably fastening a bicycle on-board device having an oblong shape along a bicycle oblong element is disclosed, wherein the support has at least one first opening configured to receive a shank of a first device for fastening to the oblong element, and a second opening configured to receive a shank of a second device for fastening to the oblong element, the first opening and the second opening being spaced along a longitudinal direction of the oblong element, the first opening being configured to receive the shank of the first fastening device alternatively in at least two first positions spaced apart in said first opening, the two first positions being spaced along a direction transversal to the oblong element.