The pneumatic tire of this disclosure comprises on a tread surface a widthwise outermost land portion partitioned by an outermost circumferential main groove and a tread edge, wherein: the widthwise outermost land portion has a plurality of side sipes extending to a tread widthwise outer side in a manner spaced from each other in the tread circumferential direction; the widthwise outermost land portion has an inner circumferential sipe and an outer circumferential sipe, the inner circumferential sipe extending in the tread circumferential direction, the outer circumferential sipe being positioned on a tread widthwise side outer than the inner circumferential sipe and extending in the tread circumferential direction; and, when h1 is a groove depth of the outermost circumferential main groove, h2 is a sipe depth of the inner circumferential sipe, and h3 is a sipe depth of the outer circumferential sipe, h1, h2 and h3 satisfy: h1>h>h2.

The crosslinkable rubber composition comprises a first elastomer consisting of polybutadiene having a Mooney plasticity ranging from 40 to 70 Mooney units, the content of the first elastomer being strictly greater than 50 phr, a second elastomer, and a carbon black having a specific surface area within a range of values extending from 15 m.sup.2/g to 25 m.sup.2/g and an oil adsorption number of compressed sample (COAN) within a range of values extending from 65 ml/100 g to 85 ml/100 g.

When the passenger-vehicle pneumatic radial tire of the disclosure is assembled to a rim and filled with an internal pressure of 250 kPa or more, an SW/OD ratio is 0.26 or less if the tire has a sectional width SW of less than 165 (mm), whereas a sectional width SW and an outer diameter OD (mm) of the tire satisfy a relation of 2.135SW+282.3OD if the tire has a sectional width SW of 165 (mm) or more, a dynamic storage modulus E at 30 C. of the tread rubber is 6.0 MPa to 12.0 MPa and a loss tangent tan at 60 C. of the tread rubber is 0.05 to 0.15, and a dynamic storage modulus E at 30 C. of the buttress rubber is or less, and a loss tangent tan at 60 C. of the buttress rubber is 0.1 or less.

When the tire is assembled to a rim and filled with an internal pressure of 250 kPa or more, an SW/OD ratio of the tire is 0.26 or less if the tire has a sectional width SW of less than 165 (mm), whereas a sectional width SW and an outer diameter OD (mm) of the tire satisfy a relation of 2.135SW+282.3OD if the tire has a sectional width SW of 165 (mm) or more, the tread rubber has a dynamic storage modulus E at 30 C. of 6.0 MPa to 12.0 MPa and a loss tangent tan at 60 C. of 0.05 to 0.15, and when a tread surface is equally divided into four regions in a tire width direction, a shoulder circumferential sipe extending in a tire circumferential direction is disposed in the shoulder portion.

In a tire 2, each load support layer 22 extends from a side portion 24 of the tire 2 to a radially inner side of a belt 14 at an inner side of a carcass 12. A ratio (SP/WB) of a width SP from an equator plane to an outer edge 48 of the load support layer 22, relative to a width WB from the equator plane to an edge of the belt 14, in an axial direction is equal to or greater than 0.1 and equal to or less than 0.6.

A run-flat tire includes a carcass including at least one carcass ply, a belt layer, a pair of side reinforcing rubber layers, a pair of bead apex rubber components. A height of the one bead apex rubber component is greater than a height of the other bead apex rubber component. An inner end height of the one side reinforcing rubber layer is greater than an inner end height of the other side reinforcing rubber layer. In a radial region of the tire where at least the bead apex rubber components and the side reinforcing rubber layers are provided, the tire has a same thickness in the respective sides of the bead portions.

A run-flat tire comprises a tread portion, sidewall portions, bead portions, and a carcass ply extending between the bead portions. The sidewall portions are each provided therein with a sidewall reinforcing rubber layer having a crescent-shaped cross sectional shape and disposed on the axially inside of the carcass ply. The sidewall portions are each provided in the axially outer surface thereof with a rim protector which projects radially outward most on the radially outside of the radially inner edge of the sidewall reinforcing rubber layer. The bead portions are each provided therein with an axially inside core and an axially outside core between which each radially inner edge portion of the carcass ply is secured. When measured along a normal line drawn normally to the carcass ply from an apex of the rim protector, the thickness of the sidewall reinforcing rubber layer is in a range of from 29% to 35% of the thickness of the tire.

This run flat tire includes a carcass toroidally extending between two bead portions and side reinforcing rubber, having a crescent cross-sectional shape in the tire width direction, on the tire width direction inside of the carcass. The relational expressions 0.09TWH/TW0.19, D/SH0.05, and 0.89TW/SW0.94 are satisfied, where, in a reference state such that the run flat tire is mounted on an applicable rim and inflated to a prescribed internal pressure with no load, TW (mm) represents the half width in the tire width direction between the tread edges, TWH (mm) represents the radial drop height of the tread edge, SW (mm) represents half of the tire maximum width, SH (mm) represents the tire cross-sectional height, and D (mm) represents the drop height of the tire at a position 0.6SW (mm) outward, in the tire width direction, from the tire equatorial plane.

The pneumatic tire of this disclosure comprises on a tread surface a widthwise outermost land portion partitioned by an outermost circumferential main groove and a tread edge, wherein: the widthwise outermost land portion has a plurality of side sipes extending to a tread widthwise outer side in a manner spaced from each other in the tread circumferential direction; the widthwise outermost land portion has an inner circumferential sipe and an outer circumferential sipe, the inner circumferential sipe extending in the tread circumferential direction, the outer circumferential sipe being positioned on a tread widthwise side outer than the inner circumferential sipe and extending in the tread circumferential direction; and, when h1 is a groove depth of the outermost circumferential main groove, h2 is a sipe depth of the inner circumferential sipe, and h3 is a sipe depth of the outer circumferential sipe, h1, h2 and h3 satisfy: h1>h3>h2.

Provided is a side-reinforced run-flat tire including a tread portion, a pair of sidewall portions extending on both sides of the tread portion, and reinforcing rubber provided in the sidewall portions, the side-reinforced run-flat tire further including: short fibers bonded, via an adhesive layer, to at least a portion of a region of a tire inner surface that is located in each of side portions, wherein the adhesive layer has a heatproof temperature of from 50 to 100 C.