An object of the present invention is to provide a pneumatic tire capable of significantly increasing the possibility that the tire can be recycled as a base tire for a retreaded tire without so much sacrificing a product life of the tire prior to retreading. Specifically, the present inventions provides a pneumatic tire 1 having a tread portion 2, plural tread grooves including a first tread groove 5 and a second tread groove 15 formed in the tread portion, and a first bottom-up portion 10 with a top surface 10a as a tread wear indicator, the first bottom-up portion being provided at a groove bottom 5b of the first tread groove 5 such that a distance measured in the tire radial direction from an opening end position 5a of the first tread groove to the top surface 10a is x1, comprising: a second bottom-up portion 20 with a top surface 20a as a retread indicator, the second bottom-up portion being provided at a groove bottom 15b of the second tread groove 15 formed in the central region 3 of the tread portion 2 such that a distance measured in the tire radial direction from an opening end position 15a of the second tread groove to the top surface 20a is x2 shorter than said x1.

A pneumatic tire includes at least four circumferential main grooves extending in the tire circumferential direction; and at least five rows of land portions including a center land portion, a pair of second land portions, and a pair of shoulder land portions, which are defined by the circumferential main grooves. Additionally, at least one row of the second land portions is provided with a plurality of lug grooves penetrating through the second land portion in the tire width direction, and a plurality of blocks defined by the plurality of lug grooves. Moreover, the plurality of blocks include one of the circumferential narrow grooves, respectively, which penetrates through the blocks in the tire circumferential direction.

A pneumatic tire includes a plurality of center lug grooves disposed at intervals in a tire circumferential direction that extend crossing a tire equator line and include a first groove turning portion and a second groove turning portion; a plurality of shoulder lug grooves disposed in the intervals between the plurality of center lug grooves in the tire circumferential direction extending outward in the tire width direction, an inner end in the tire width direction being disposed outward of an end of the center lug groove in the tire width direction; a pair of circumferential main grooves to which the ends of the center lug grooves and the inner ends of the plurality of shoulder lug grooves in the tire width direction alternately connect; and a circumferential secondary groove disposed around the entire circumference of the pneumatic tire with a wave-like shape.

A plurality of main grooves extending from a tread center region including a tire equator to ground contact ends so as to be inclined with respect to a tire width direction are provided on a tread section at intervals in a tire circumferential direction. Sub-grooves extending in a direction crossing the tire width direction with a narrower groove width than the main grooves in the tread center region are provided. Tie bars connecting blocks separated by the sub-grooves are provided inside the sub-grooves.

A tire tread having features that improve thermal wear performance is provided. A tread block is provided with an aperture. The aperture is positioned and sized in a manner that reduces stresses and/or strains in the tread block so as to reduce thermal wear. Certain variations in the depth and shape of the aperture are provided. Such tread feature can provide for a tire capable of operating at higher speeds for a given load.

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 tread pattern is provided with: shoulder lug grooves open at ground contact ends; center lug grooves each having opposite ends; circumferential primary grooves each formed in a wavy shape by connecting ends of the center lug grooves and the inner ends of the shoulder lug grooves in the width direction of the tire; and center blocks defined by the center lug grooves and the pair of circumferential primary grooves. The width of the circumferential primary grooves is smaller than the width of the shoulder lug grooves. The center lug grooves are tilted relative to both the circumferential direction and the width direction of the tire and each have a third groove turning portion and a fourth groove turning portion which protrude in the different directions in the circumferential direction of the tire.

A tread surface of a pneumatic tire is configured so that, given an inner region inward from shoulder circumferential main grooves in a tire lateral direction, and outer regions outward from the shoulder circumferential main grooves in the tire lateral direction, blocks positioned in the inner region are defined into three or more small blocks by narrow grooves, and blocks positioned in the outer regions are defined into a number of small blocks by the narrow grooves, the number being at least one less than the number of small blocks defined in the blocks positioned in the inner region. The small blocks including frontmost portions of the blocks in a tire rotation direction are leading-side blocks, and the small blocks including backmost portions of the blocks in the tire rotation direction are trailing-side blocks. The leading-side blocks have a surface area that is less than that of the trailing-side blocks.

A pneumatic tire comprises a tread portion 2 provided with shoulder axial grooves 10 extending from a shoulder main groove 3 to a tread edge Te while inclining to a first-side in the tire circumferential direction. The shoulder axial groove 10 has a first-side groove edge, a second-side groove edge, a first-side groove-sidewall 14 extending radially inward from the first-side groove edge 12, and a second-side groove-sidewall 15 extending radially inward from the second-side groove edge 13. The shoulder axial groove 10 has a part where the inclination angle β of the first-side groove-sidewall 14 with respect to a normal line passing through the first-side groove edge 12 perpendicularly to the tread surface 2s is more than the inclination angle α of the second-side groove-sidewall 15 with respect to a normal line passing through the second-side groove edge 13 perpendicularly to the tread surface 2s.

A tire is a tire in which circumferential grooves, and lug grooves comprising opening portion in tread end and which extend in the tread width direction from the tread end to the circumferential groove, are formed. Projection parts are provided in the groove bottom of the circumferential grooves. The projection parts extend from one side wall forming a circumferential groove to the other side wall opposite the one side wall. Multiple lug grooves are formed at predetermined intervals in the circumferential direction. In the tread surface view of the tire, given points of intersection as the points at which a circumferential groove extension that passes through a circumferential groove intersects with a lug groove extension that passes through a lug groove, the projection parts are provided between a first point of intersection and a second point of intersection adjacent to the first point of intersection in the circumferential direction.