Tire with specified belt profile in the absence of load and inflating pressure

A tire for motor-vehicle wheels comprising a toroidal carcass provided with axially opposite sidewalls and beads for anchoring of said tire to a corresponding mounting rim, a tread band disposed crown-wise to said carcass and a belt structure interposed between said carcass and tread band, axially extended in a continuous manner between said sidewalls, said tread band being molded with a raised pattern having a circumferential groove, wherein in the absence of load and inflating pressure, said belt structure, seen in cross section in the plane containing the tire axis, has:

• an axial profile comprising three distinct portions, two side portions referred to as first and second portions, and one central portion respectively, said central portion being interposed between said side portions;
• said side portions being concave at a radially internal position, in which the concavity is defined for each side portion by a respective center and a respective radius of curvature,
• said central portion being concave at a radially external position, the concavity center of said central portion lying in the center line plane of said circumferential groove, in which the depth of said radially external concavity is canceled under the effect of the normal inflating pressure of the tire, and
• the depth of the radially external concavity corresponds to an amount of expansion which the tire mounted to said corresponding rim and subsequently inflated would undergo if said belt structure viewed in an axial cross section were defined by a continuously concave profile at a radially internal position.