A tread surface 20 of the tire 2 includes a center portion C and a pair of shoulder portions S. A contour line of the tread surface 20 is divided into ten parts. Among the ten parts, two parts including an equator PC are represented by arcs, and two parts including ends PE of the tread surface 20, respectively, are represented by arcs. A degree of curvature of each shoulder portion S is higher than a degree of curvature of the center portion C. A ratio of the degree of curvature of the shoulder portion S to a width TW of the tread surface 20 is not less than 50%. A ratio of the degree of curvature of the center portion C to the width TW of the tread surface 20 is not greater than 70%.

A tread surface 20 of the tire 2 includes a center portion C and a pair of shoulder portions S. A contour line of the tread surface 20 is divided into ten parts. Among the ten parts, two parts including an equator PC are represented by arcs, and two parts including ends PE of the tread surface 20, respectively, are represented by arcs. A bank angle θb is larger than a camber angle θc. A ratio of a degree of curvature Bs of the shoulder portion S to a width TW of the tread surface 20 is not less than 50%. A ratio of a camber height d to a tire cross-sectional height H is not less than 50%.

In a tire meridian cross-section in a 5% internal pressure state of a heavy duty tire, a first radius of curvature of a first ground-contact surface profile of each of a center land portion, an inner region of a first middle block, an outer region of the first middle block, and a first shoulder block can be defined. In addition, a ratio (Wa/Da) of a groove width Wa to a groove depth Da of a center circumferential groove may not be larger than 0.25. Furthermore, a ratio (Lb/La) of a maximum length Lb in a tire axial direction to a maximum length La in a tire circumferential direction in the first middle block can be defined.

A tire has a block pattern. The block pattern includes a plurality of linked block pairs. Each linked block pair includes two blocks 28 and a tie bar 30 interposed between the two blocks 28 and linking the two blocks 28 together. The tie bar 30 has a toe end 40 having a height equal to or smaller than a height of the blocks 28 and a heel end 38 having a height smaller than the height of the toe end 40.

A pneumatic tire is provided with, in the tread surface, land portions that include a rib or a plurality of blocks. The land portions are provided with a plurality of narrow shallow grooves and a plurality of recessed portions in a contact patch. Additionally, the opening area ratio Sc of the recessed portions in the central portion region in the tire lateral direction of one continuous contact patch and the opening area ratio Se of the recessed portions in the end portion regions in the tire lateral direction have the relationship Se<Sc, where the central portion region is defined as the region in the central portion in the tire lateral direction occupying 50% of the continuous contact patch of the land portions, and the end portion regions are defined as the regions in the left and right end portions in the tire lateral direction occupying 25%.

Tire tread (1) is divided into central part (20) and edge parts (30), central part (20) having width Lc between 40% and 90% of total width W of the tread. Edge parts (30) do not have any transverse cuts. Central part (20) has a tread pattern with circumferentially oriented sipe (21) and transversely oriented sipes (22, 22′, 22″) distributed around the periphery of the tread, such sipes having a depth at least equal to 60% of thickness E of material to be worn away and being interconnected to form a network. Such sipes are continued by hidden channels (210, 220). Central part (20) is delimited axially by transverse sipes (22′, 22″), each of which ends in end channel (221′, 221″) that opens onto tread surface (10) and extends into the thickness of the tread, and each end channel (221′, 221″) is connected to the network formed by the hidden channels.

A tire (10) for a passenger vehicle comprises a tread comprising at least one regulation wear indicator (46) defining a regulation wear threshold, a tread layer (52) comprising an elastomeric tread material exhibiting a complex dynamic shear modulus G*_1 and a dynamic loss tanD0_1, and a backing layer (54) for the tread layer (52) that comprises an elastomeric backing material exhibiting a complex dynamic shear modulus G*_2 and a dynamic loss tanD0_2 such that tanD0_2≥0.37×tanD0_1 and G*2≥0.90×G*1.

A tire has a tread comprising at least two tread pattern elements (MA, MB) distributed periodically in the circumferential direction at pitches (PA, PB). Each tread pattern element is formed of three portions (Z1, Z2, Z3), each defining a volumetric element of which the trailing edge corner is the one common to the tread surface and is the last to leave the contact patch in which the tire is in contact with the ground. With each trailing edge corner being chamfered, in the portions Z1 and/or Z2, and/or Z3, the widths of the chamfers of the trailing edge corners (LC.sub.i.sup.A, LC.sub.i.sup.B, i ranging from 1 to 3) ef satisfy the following inequalities: a)

[00001]$0.8*\frac{PA}{PB}\le \frac{L{C}_1^A}{L{C}_1^B}\le \frac{PA}{PB}*1.2$

for the portion Z1, b)

[00002]$0.8*\frac{PA}{PB}\le \frac{L{C}_2^A}{L{C}_2^B}\le \frac{PA}{PB}*1.2$

for the portion Z2, and c)

[00003]$0.8*\frac{PA}{PB}\le \frac{L{C}_3^A}{L{C}_3^B}\le \frac{}{}$

Provided is a pneumatic radial tire for a passenger car that exhibits both riding comfort at low temperatures and stealing stability at high-speed running. The present invention is a pneumatic radial tire for a passenger car, in which: a carcass and a tread are provided; the tread is integrated into a standardized rim; when internal pressure is at a standardized internal pressure, the tire has a cross-sectional width Wt (mm) and an outer diameter Dt (mm) satisfying 1963.4≤(Dt.sup.2π/4)/Wt≤2827.4; the tread comprises at least one main groove in a running surface of the tread, extending in the circumferential direction of the tread; the land/sea ratio at the tread running surface is greater than 55% and less than 85%; and a rubber composition that forms the tread has a loss tangent (tan δ) which, when measured at a frequency of 10 Hz, an initial strain of 2%, and a dynamic strain rate of 1%, is such that |20° C. tan δ-50° C. tan δ| is at least 0.01 and less than 0.15, and 15° C. tan δ-20° C. tan δ| is greater than 0.15 and less than 0.70.

A tire includes a block 30. The block 30 includes a land 36b, a transverse groove 48b, a longitudinal groove 50b, and a side surface 38b. The land 36b is flat. The transverse groove 48b is recessed from the land 36b. The transverse groove 48b has inner and outer ends 52 and 54 in an axial direction of the tire. The inner end 52 of the transverse groove 48b is open on the side surface 38b. The outer end 54 of the transverse groove 48b is not open on the side surface 38b. The transverse groove 48b is localized in the inner region of the block 30 in the axial direction.