A heavy-duty pneumatic tire includes a tread pattern including center lug grooves, shoulder lug grooves, a pair of circumferential primary grooves formed in wave-like shapes by alternately connecting ends of the center lug grooves and ends of the shoulder lug grooves and having a smaller width than the width of the shoulder lug grooves, center blocks defined by the center lug groove and the circumferential primary grooves, and a circumferential secondary groove extending in the tire circumferential direction so as to divide regions of the center blocks. The belt portion includes two or greater pairs of belts. The ratio of the width W8 of a belt having a smaller width in each of the belt pairs to the width W7 of a belt having a greater width is 0.75 or greater and 0.90 or less.

A pneumatic tire includes a tread portion provided with a circumferentially extending zigzag shoulder main groove arranged proximate to a tread edge, and a plurality of shoulder lateral grooves each extending axially outwardly from the shoulder main groove. Each of the shoulder lateral grooves includes a first portion and second portion. The first portion includes a first groove wall and an axially inner end connected to the shoulder main groove. The second portion is arranged axially outward of the first portion and includes a second groove wall. The second portion has a groove width and a groove depth greater than those of the first portion. The first groove wall of the first portion and the second groove wall of the second portion are smoothly continued.

A pneumatic tire includes a tread portion provided with at least one circumferentially extending main groove, and at least one lateral groove extending from the main groove. The at least one lateral groove comprises a bottom, and at least one stepwise groove wall that includes at least one level part, wherein the number of level part is not more than three. In a cross-sectional view of the lateral groove, a depth Da from a ground contacting surface of the tread portion to a radially innermost level part is in a range of from 50% to 80% a maximum groove depth D4 of the lateral groove, and a width Wa from the radially innermost level part to a groove edge of the stepwise groove wall measured along in a groove width direction is in a range of from 50% to 150% the depth Da.

The present technology provides a heavy duty pneumatic tire with a tread portion having a tread pattern including: a pair of circumferential primary grooves defined in a wave-like shape and extending in the tire circumferential direction; center lug grooves; center blocks; and circumferential secondary grooves extending in regions of the center blocks and open to the center lug grooves. The center lug grooves have two groove turning portions turned in a bend shape or a curved shape. The circumferential secondary grooves extend in an inclined manner relative to the tire circumferential direction. An inclination angle (θ.sub.4) of the circumferential secondary grooves relative to the tire circumferential direction is different from an inclination angle (θ.sub.1) of portions of the circumferential primary grooves relative to the tire circumferential direction, the portions extending toward the same side as a side in the tire width direction, toward which the circumferential secondary grooves are inclined.

A tire has a lug that forms a contact patch surface, and a recessed region that extends along a prescribed direction and that is recessed relative to the contact patch surface. The recessed region has a first vertical face that that forms a first edge between the first vertical face and the contact patch surface, and a planar base that extends in a width direction of the recessed region which is perpendicular to the prescribed direction. The planar base has at least two planar regions having mutually different heights and arrayed along the prescribed direction. The recessed region further has a second vertical face that connects the two planar regions and that forms a third edge between the second vertical face and a higher one of the planar regions. The third edge is inclined with respect to both a tire width direction and a tire circumferential direction.

A pneumatic tire comprising a tread portion provided with a middle land portion 6 which is arranged between a central main groove 3 and a shoulder main groove 4. The middle land portion 6 is provided with an inner middle lateral groove 8 and an outer middle lateral groove 9. The inner middle lateral groove 8 comprises a first inclined portion 10 that extends axially outwardly from the central main groove 3 at an angle θ1 of from 10 to 40 degrees with respect to a circumferential direction of the tire, and a second inclined portion 12 that is inclined at an opposite direction to the first inclined portion 10 so as to extend axially inwardly, and a bent portion 11 connecting the first inclined portion 10 and the second inclined portion 12. The outer middle lateral groove 9 is communicated with the second inclined portion 12 of the axially inner middle lateral groove 8 without including an axially outermost groove edge 8e of the inner middle lateral groove 8, and is communicated with the shoulder main groove 4. The axially outer middle lateral groove 9 is inclined in the same direction of the first inclined portion 10 of the inner middle lateral groove 8 at an angle θ3 of from 30 to 70 degrees with respect to the circumferential direction of the tire.

A pneumatic tire includes, on a tread surface, a plurality of circumferential main grooves extending in the tread circumferential direction, and a plurality of land portions each defined between circumferential main grooves adjacent in the tread width direction among the plurality of circumferential main grooves, or by a circumferential main groove and a tread edge. A widthwise groove (widthwise sipe) (circumferential sipe) includes a widened portion, on the groove bottom side (sipe bottom side), at which the groove width (sipe width) is larger than on the tread surface side.

The storage modulus of tread rubber located in a tire radial direction region including at least a reference depth position is larger than a storage modulus of tread rubber located in regions inward and outward in the tire radial direction from the tire radial direction region.

A pneumatic tire includes, on a tread surface, a plurality of circumferential main grooves extending in the tread circumferential direction, and a plurality of land portions defined by circumferential main grooves adjacent in the tread width direction among the plurality of circumferential main grooves, or by the circumferential main grooves and tread edges. A widthwise groove (widthwise sipe) (circumferential sipe) includes a widened portion, on the groove bottom side (sipe bottom side), at which the groove width (sipe width) is larger than on the tread surface side. In a tire radial direction region including at least a reference depth position, the storage modulus of first tread rubber, which is a groove wall surface layer defined by the widened portion and covering at least part of the widened portion, is larger than the storage modulus of second tread rubber located in a region around the first tread rubber.

The present invention provides a tire having a good balance of fuel efficiency, chipping resistance, and steering stability.

A pneumatic tire includes fins disposed on sidewall surfaces of blocks and extending in a tire circumferential direction. Further, a plane is local and is defined to include a ground contact edge of the first and second blocks and an arc connecting opening end portions of three lug grooves defining the first and second blocks. At this time, the fins of the first and second blocks extend sidewalls of the lug grooves further toward an outer side in a tire width direction than the plane via one circumferential edge portions of the blocks. Furthermore, the projection amount of the fins with respect to the plane tapers from the one circumferential edge portions toward other circumferential edge portions of the blocks.