Tire having optimized performance in terms of rolling resistance without impairing the industrial performance

A tire for a passenger vehicle comprising in a meridian plane:

• two beads intended to be mounted on a rim, two sidewall layers connected to the beads, a crown comprising a tread, the crown having a first side connected to a radially outer end of one of the two sidewall layers and having a second side connected to a radially outer end of the other of the two sidewall layers;
• and
• at least one carcass reinforcement extending from the two beads to the crown, the at least one carcass reinforcement comprising a plurality of carcass reinforcement elements and being anchored in the two beads by a turn-up around an annular reinforcement structure, so as to form in each bead a main part and a turn-up,
• wherein each sidewall layer consists of two axially superposed sub-layers, a first sidewall sub-layer delimited by a first axially outermost side constituting a lateral wall of the tire in contact with ambient air, and a second axially inner side defined such that the sidewall sub-layer has an average axial thickness E1, and occupying a volume V1, and a second sidewall sub-layer, a first side of which coincides with the second axially inner side of the first sidewall sub-layer, and a second, axially inner side of which is at least partially in contact with the carcass reinforcement, the sidewall sub-layer having an average axial thickness E2, and occupying a volume V2,
• wherein the thickness E1 of the first sidewall sub-layer is greater than or equal to 0.7 mm,
• wherein a ratio V1/(V1+V2) is less than or equal to 0.3,
• wherein an elongation at break of an elastomer compound constituting the first sidewall sub-layer is greater than or equal to 200% measured at a temperature of 100° C., and
• wherein a viscoelastic loss of the second sidewall sub-layer, Tan(δ) max, is less than or equal to 0.10.