Motor vehicle tire with low rolling resistance

A tyre for a motor vehicle, comprising:

• at least one carcass ply;
• a belt structure in a radially-external position relative to the at least one carcass ply;
• a tread band in a radially-external position relative to the belt structure;
• a pair of sidewalls in axially-external positions relative to the at least one carcass ply;
• and
• a pair of beads;
• wherein the beads comprise bead wires or circumferentially-inextensible annular inserts,
• wherein opposite lateral edges of the at least one carcass ply are associated with respective beads,
• wherein the at least one carcass ply comprises a first composition comprising an elastic modulus at 70° C. less than or equal to 5.0 MPa and a viscous modulus at 70° C. less than or equal to 0.50 MPa, and
• wherein the sidewalls comprise a second composition comprising an elastic modulus at 70° C. greater than or equal to 3.5 MPa and a viscous modulus at 70° C. less than or equal to 0.50 MPa.