The invention relates mainly to a wheel system (S) intended to be rotationally driven about a central axis (X), comprising two distinct parts (R1, R2) arranged in such a way as to be in pivoting connection with one another about the central axis (X), the wheel system (S) is designed in such a way as to occupy two positions； a first position, referred to as the mounted position, in which the two distinct parts (R1, R2) are superposed, and a second position, referred to as the standard position, in which the two distinct parts (R1, R2) are angularly offset from one another so as to form a disc in the plane (P) perpendicular to the central axis (X), the transition from the mounted position to the standard position being carried out by means of a translational movement, along the central axis (X), of one of the distinct parts (R2) with respect to the other (R1).
