The invention concerns a rear part (4) of a vehicle (1) that comprises a rear structure (41) and a spare wheel (3), the rear structure (41) comprising a luggage compartment floor (43) in which a well (44) is formed in order for said spare wheel (3) to be positioned therein, the well (44) comprising a bottom (47) and at least one first wall positioned facing the spare wheel (3) and forming a rear wall or one of the two side walls of the well, the bottom of the well comprising attachment means (6) for securing the spare wheel (3) thereto, the well (44) comprising control means (7) positioned between said first wall (45) and the attachment means (6), said control means (7) being suitable for releasing the spare wheel (3) from the bottom (47) of the well (44) in the event of an impact against said rear part (4) of the vehicle, on the side of the first wall (45) of the well (44), in alignment with the control means (7).