A pneumatic tire includes a tread portion having a tread rubber and a tire inner cavity surface, and a noise damper made of a porous material fixed to the tire inner cavity surface. The tread rubber includes an outer tread rubber having a ground-contacting surface, and an inner tread rubber disposed inwardly in the tire radial direction of the outer tread rubber and outwardly in the tire radial direction of the noise damper. A loss tangent tan δ of the inner tread rubber at 30° C. is smaller than a loss tangent tan δ of the outer tread rubber at 30° C.

It is an object to provide a tire having an excellent balance of wet grip performance and chipping resistance. The tire is a tire comprising a tread, wherein the tread has a lateral groove neither of both ends of which opens into circumferential grooves, wherein a predetermined rubber component, a predetermined filler, and a silane coupling agent are compounded in a rubber layer of a tread surface, wherein a brittleness temperature of the rubber component and a ratio of a groove depth at the deepest part of the groove bottom of the lateral groove neither of both ends of which opens into the circumferential grooves to a thickness of the entire tread are made to lie in predetermined ranges.

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.

In a tire, a tread includes a cap layer forming a part of an outer surface of the tire, a base layer disposed inwardly of the cap layer in a radial direction, and an intermediate layer disposed between the cap layer and the base layer in the radial direction. A loss tangent of the intermediate layer at 30° C. is less than a loss tangent of the cap layer at 30° C. and a loss tangent of the base layer at 30° C. is less than the loss tangent of the intermediate layer at 30° C. The tread includes at least two three-layer body portions formed of the cap layer, the intermediate layer, and the base layer, and at least one two-layer body portion that is formed of the cap layer and the base layer and disposed between a first three-layer body portion and a second three-layer body portion.

A pneumatic tire comprising a tread composed of a rubber composition containing 30 to 120 parts by mass of silica having a BET specific surface area of 180 to 280 m.sup.2/g based on 100 parts by mass of a rubber component, wherein, under a normal state with no load where the pneumatic tire is mounted with a normal rim and filled with a normal internal pressure, a grounding surface shape in which a normal load is applied and the tread is pressed against a plane surface satisfies the following equation (1): 0.95≤SL0/SL80≤1.6 (wherein, SL0 is a ground contact length in a circumferential direction of the tire on a tire equator, and SL80 is a ground contact length in a circumferential direction of the tire on a position away from the tire equator by a distance in a tire axial direction of 80% of a tread grounding half width.)

A pneumatic tire comprises a tread portion provided with a pair of crown main grooves and a pair shoulder main grooves to divide middle portions and shoulder portions, the tread portion having a contact surface covered with a cap rubber layer with a loss tangent of from 0.03 to 0.18, the middle portions provided with only middle lug grooves with groove widths within 2 mm, each middle lug groove extending from one end connected either the crown or shoulder main groove to the other end terminating within the middle portion, the middle lug grooves having an angle of from 40 to 55 degrees with respect to a tire circumferential direction, and each shoulder portion provided with first shoulder lateral grooves having axially inner ends connected to the shoulder main groove, wherein first shoulder lateral grooves consist of grooves having groove widths within 2 mm.

When a tire is attached to a rim and set to an internal pressure of 250 kPa or more, a ratio SW/OD of the tire is 0.26 or less in the case where SW of the tire is less than 165 (mm), and SW and OD satisfy a relationship 2.135×SW+282.3≦OD in the case where SW is 165 (mm) or more. The tread rubber has dynamic storage modulus E′ of 6.0 MPa to 12.0 MPa, and loss tangent tan δ of 0.05 to 0.15. In at least one land portion, sipes are arranged with a predetermined pitch length L, and a land portion width W, a tire widthwise sipe component total length Ws of the sipes, the pitch length L, and a tire circumferential sipe component total length Ls of the sipes satisfy relationships 0.4W≦Ws≦1.2W and 0.6L≦Ls≦3L.

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.

The invention provides for a heavy truck tire having a sub-casing, a belt package and a rubber tread, the tread comprising a center zone separating two shoulder zones. The upper shoulder layer consisting of an upper shoulder rubber compound being different from a lower shoulder rubber compound, wherein: the upper shoulder rubber compound has a G*50 of at least 1.3 Mpa and a max tan(δ) of at least 0.12; the lower shoulder rubber compound has a max tan(δ) not greater than the max tan(δ) of a center rubber compound in the center zone being intended to come into contact with the ground; and the center rubber compound has a max tan(δ) of at most 0.09.

A pneumatic tire includes: a rim cushion rubber disposed in a bead portion where the bead portion and a rim are in contact with each other; an electrically conductive rubber disposed in the rim cushion rubber, the electrically conductive rubber having an electrical resistance value lower than that of the rim cushion rubber, and including a first end exposed on an outer surface of the rim cushion rubber in contact with the rim, and a second end disposed in contact with a tire component adjacent to the rim cushion rubber; and an earth tread rubber disposed in a tread portion passing through a cap tread rubber and an undertread rubber of the tread portion, the earth tread rubber having an electrical resistance value lower than that of the cap tread rubber.