A tire 22 includes a plurality of ribs 68 aligned in an axial direction. A rib 68s, among the plurality of ribs 68, disposed on an outer side in the axial direction is sectioned into a body portion 74 and a side portion 76 by a groove 72 that extends in a circumferential direction. The tire 22 includes a tread 26 and a pair of sidewalls 28. The sidewalls 28 extend almost inward from ends, respectively, of the tread 26 in a radial direction. The tread 26 includes a base layer 52, and a cap layer 54 disposed outward of the base layer 52 in the radial direction. The side portion 76 is formed by the cap layer 54 and a corresponding one of the sidewalls 28. The sidewall 28 is stacked on the cap layer 54 in the side portion 76.

A heavy truck tire is provided that includes a tread and a casing. The casing has a bead with a bead core having padding gum and a rod with a perimeter. A contention armature surrounds the bead core and has an overlap, a majority of which is located outward in the radial direction from the rod. The padding gum is arranged in relation to the rod such that an outer area, inner area, and an axially outer area of the padding gum have areas that are greater than or equal to 20% of the area of the perimeter of the rod. An axially inner area of the padding gum is greater than or equal to 10% of the area of the perimeter of the rod.

A pneumatic tire comprises a carcass layer, a belt layer disposed on an outer side of the carcass layer in a tire radial direction, and a tread rubber disposed on the outer side of the belt layer in the tire radial direction. The belt layer formed by laminating an angle belt having a belt angle≧45° and ≦70° in absolute values, a pair of cross belts, having belt angles of ≧10° and ≦45° in absolute values and having belt angles of mutually opposite signs, and a circumferential reinforcing layer having a belt angle within a range of ±5° with respect to a tire circumferential direction. A tread width TW and a total tire width SW such that 0.79≦TW/SW≦0.89. A width Ws of the circumferential reinforcing layer and a cross-sectional width Wca of the carcass layer such that 0.60≦Ws/Wca≦0.70.

A pneumatic tire for heavy duty having an aspect ratio of 65% or less includes a carcass and a belt layer. A tread portion includes circumferential grooves. The circumferential grooves include a pair of shoulder circumferential grooves and a crown circumferential groove. The crown circumferential groove 11 is a narrow groove and each of the shoulder circumferential grooves is a wide groove. The belt layer includes metal belt cords inclined with respect to a tire circumferential direction. The belt layer has outer ends each positioned outside a respective one of the shoulder circumferential grooves in a tire axial direction. A belt half width is 55% or more and 85% or less of a carcass half width.

A tire rubber composition according to an embodiment contains: 20 parts by mass to 45 parts by mass of carbon black and 5 parts by mass to 30 parts by mass of silica with respect to 100 parts by mass of a diene rubber containing a tin-modified polybutadiene rubber; a compound represented by a General Formula (1) and/or a compound represented by a General Formula (2); and a silane coupling agent. In the Formula (1), R.sup.1 and R.sup.2 represent a hydrogen atom, an alkyl group, an alkenyl group, or an alkynyl group, and M.sup.+ represents Na.sup.+, K.sup.+, or Li.sup.+. In the Formula (2), A represents an aromatic ring group, a hydantoin ring group, or a linear hydrocarbon group.

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Tread for heavy-duty vehicle tire, having tread surface with at least one cavity forming a hidden channel which forms an additional groove after an amount of wear, each channel extended towards tread surface in the new state along its entire length by a sipe of small width, at least one channel having plurality of extensions from this channel towards tread surface to place the channel and the outside of the tread into communication from an amount of partial wear of the tread, each extension being a secondary channel having a first opening of elongate shape with a minimum dimension I0 and a maximum dimension Lo that opens onto tread surface and a second opening that opens into channel, wherein for at least one channel provided with extensions, each first opening of these extensions is formed by a side of the sipe that extends the channel.

A heavy duty tire has a carcass extending from a tread portion to a bead core in a bead portion through a sidewall portion, and a belt layer disposed on the outside of the carcass in the tire radial direction and on the inside of the tread portion. In a state in which a distance between a pair of bead heels is kept at 110% of a wheel rim width of a standard wheel rim and no inner pressure is applied, the contour shape of the tread portion is formed by a 1st circular arc having a center on the tire equatorial plane, and a pair of 2nd circular arcs, disposed on both outsides of the 1st circular arc in the tire axial direction. The radius of the 2nd circular arc is more than the radius R1 of the 1st circular arc. One 2nd circular arc has the center on the other 2nd circular arc side of the tire equator in the tire axial direction, and the other 2nd circular arc has the center on the one 2nd circular arc side of the tire equator in the tire axial direction.

OD is defined by an outer diameter of the pneumatic tire, RW is defined by a rim width of a rim wheel assembled to the pneumatic tire, SW is defined by a tire width of the pneumatic tire, and RD is defined by a rim diameter of the pneumatic tire, the OD is 350 mm or more and 600 mm or less, the relation of 0.78≤RW/SW≤0.99; and the relation of 0.56≤RD/OD≤0.75 are satisfied.

A heavy duty pneumatic tire includes a tread portion provided with at least one circumferentially extending main groove, at least one circumferentially extending sub groove, and a plurality of lateral grooves to form repeated pitch elements each of which consists of one lateral groove and a block element. The sub groove includes a shallow bottom part with a depth smaller than that of the main groove. The shallow bottom part of the sub groove is provided with a groove bottom sipe. The lateral grooves include a shallow bottom part with a depth smaller than that of the main groove. The shallow bottom part of the lateral groove is provided with a groove bottom sipe. The lateral grooves have groove widths W2 in a range of from 5% to 15% in relation to a circumferential length L1 of the pitch element.

A heavy duty tire is disclosed. The distance from the radially outer surface of a belt layer to the tire's inner surface is 15 to 23 mm when measured along a tire radial direction line passing through the bottom of a shoulder main groove. The width of the shoulder main groove is more than the width of a center main groove. The ratio Wc:Wm:Ws of the average width Wc of a center land portion, the average width Wm of a middle land portion, and the average width Ws of a shoulder land portion is 1.00:1.00 to 1.08:1.03 to 1.13. The middle land portion is provided with a plurality of middle axial grooves. The shoulder land portion is provided with a plurality of shoulder axial grooves. The width of the shoulder axial groove is more than the width of the middle axial groove. The angle θs of the shoulder axial groove is more than the angle θm of the middle axial groove with respect to the tire axial direction.