Wheel and tire assembly with non-matching seat diameters whereof the tire comprises sidewalls wider than the rim

An assembly comprising:

• a vehicle wheel, with symmetry of revolution, comprising a disc and a rim, the said rim comprising a first and a second seat which seats are intended to receive and to hold a first and a second bead of the tire, each seat having a substantially frustoconical bottom locally coinciding with a cone of revolution coaxial with the rim and open towards the other seat, and an external flange extending the bottom of the said seat in the direction away from the other seat and comprising an outer portion, the said rim defining, at the level of an axial straight line passing through the farthermost points of the outer portions, a width Lj;
• and, on the other hand, a tire for a vehicle wheel, comprising:
• two sidewalls spaced axially apart and defining, at the level of an axial straight line passing through the farthermost points of the said sidewalls, a width Lf, the said sidewalls each having, at the level of an axial straight line passing through the farthermost points of the said sidewalls, a width shorter than the width of the said sidewalls measured at a point substantially adjacent to the beads, the said sidewalls being connected to their radially outer portions by a crown region the width of which is shorter than the said width Lf and the said crown region being provided on its radially outer portion with a circumferential tread;
• beads, positioned radially internally with respect to each of the sidewalls, each bead comprising a seat and an external flange which are intended to come into contact with the said rim;
• a reinforcing structure extending substantially radially from each of the beads, along the sidewalls towards the crown region;
• at least one of the said beads comprising:
• a bead seat comprising a generatrix, the axially inner end of which lies on a circle of diameter greater than the diameter of the circle on which the axially outer end lies;
• an anchoring region where the reinforcing structure is anchored in the said bead;
• wherein, when the said tire is mounted on the said rim and inflated close to its nominal working pressure and when the said tire is substantially unflattened, said width Lf is greater than the said width Lj.