In a pneumatic tire 2 according to the present invention, in the vicinity of a bead 10 portion, a main portion 42 of a carcass ply 40 is passed through the vicinity of a neutral surface. A tensile force and a compressive force applied to the main portion 42 are small. In the tire 2, occurrence of pinch cut is suppressed. In addition, this structure alleviates a force applied to the main portion 42 even during run-flat running. In the tire 2, damage is less likely to occur even during run-flat running for a long period of time. The tire 2 has excellent run-flat durability. Furthermore, in the tire 2, an increase in the vertical stiffness constant or weight thereof is suppressed.

A run-flat tire includes reinforcing rubber in a sidewall, first bead filler rubber disposed toward the inside of a folded back portion of a carcass layer in a lateral direction, and second bead filler rubber disposed toward the outside of the folded back portion in the lateral direction. The reinforcing rubber has a thickness from a rim base line to a position within 38% to 68% of a tire cross-sectional height being from 90% to 100% of a maximum thickness of the reinforcing rubber. In a range from a position of a rim check line to a position being 38% of the tire cross-sectional height from the rim base line, a total thickness of the reinforcing rubber, the first bead filler rubber, and the second bead filler rubber is from 100% to 140% of the maximum thickness of the reinforcing rubber.

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 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.

In a side reinforcing type tire 2, when a cross-sectional height of the tire 2 is denoted by L, a height in a radial direction from a bead base line to an outer edge of a core 34 is denoted by HC, a point on a turned-up portion 42 of a carcass ply 38 at which point a height in the radial direction from the bead base line is 0.35 times of the height L is denoted by P1, and a point on the turned-up portion 42 at which point the height in the radial direction from the bead base line is equal to the height HC is denoted by P2, the turned-up portion 42 has, between the point P1 and the point P2, a shape that is a curved line projecting inward in an axial direction, a straight line, or a combination thereof.

A tire suitable for running flat comprises a crown, two sidewalls and two beads, a carcass reinforcement anchored in each bead and a sidewall insert placed in each of the two sidewalls axially internally relative to the carcass reinforcement, such that it is equipped with an electronic device comprising at least one radiofrequency transponder and such that the electronic device is placed radially in a zone representing over 55% of the section height of the tire.

A run-flat tire includes side reinforcing rubber between a carcass layer and an innerliner layer in sidewall portions, first bead filler rubber arranged inside folded back portions of the carcass layer, and second bead filler rubber arranged outward of the folded back portions of the carcass layer in a lateral direction. In a meridian cross-section, a radial-direction height of the first bead filler rubber is 15% or greater and 40% or less of a cross-sectional height, a radial-direction height of the second bead filler rubber is 35% or greater and 55% or less of the cross-sectional height, a linear distance from a radial-direction outer end to a radial-direction inner end of the second bead filler rubber is 20% or greater and 45% or less of the cross-sectional height, and the second bead filler rubber has a larger cross-sectional area than the first bead filler rubber.

A pneumatic tire comprises a carcass formed of a carcass ply extending between a pair of bead portions in a toroidal shape, and a bead core disposed in a respective one of the bead portions, the bead core comprising an axially inner core and an axially outer core respectively disposed on an axially inner side and the axially outer side of the carcass ply. The bead portion comprises an inner bead apex rubber extending radially outward from the inner core, and an outer bead apex rubber extending radially outward from the outer core. An outer apex height Ho from a bead base line to a outer end of the outer bead apex rubber is in a range of from 120% to 150% of an inner apex height Hi from the bead base line to the outer end of the inner bead apex rubber.

A method of preparing a sidewall support, the method comprising the steps of (i) providing a vulcanizable composition including an elastomer, a filler, a curative, and a eutectic composition; (ii) fabricating the vulcanizable composition into a green sidewall support; and (iii) subjecting the green sidewall support to curing conditions.

The present invention relates to a self-supporting tyre (100) for motor vehicles which comprises sidewall reinforcing inserts (113A, 113B) with different stiffness. In particular, the sidewall reinforcing insert on the side of the tyre most stressed during driving is less rigid than the sidewall reinforcing insert on the less stressed side. The tyre of the invention exhibits a reduced rolling resistance and better comfort in normal driving and an unexpected increase in mileage in run-flat driving.