The run-flat tire of this disclosure includes a tread portion, a pair of sidewall portions continuous, bead portions, side reinforcing rubbers with crescent-like cross section, and a carcass, wherein: when the tire is mounted to a rim, and an internal pressure of 250 kPa or more is applied, in a case where a sectional width SW of the tire is less than 165 mm, a ratio of the sectional width SW to an outer diameter OD of the tire, SW/OD, is 0.26 or less; and in a case where the sectional width SW of the tire is 165 mm or more, the sectional width SW and the outer diameter OD of the tire satisfy a relation expression OD≧2.135×SW+282.3 (mm); and when H1 is a tire radial maximum length of the side reinforcing rubber in a tire widthwise cross section in a reference state, a relation expression 10 (mm)≦(SW/OD)×H1≦20 (mm) is satisfied.

A tire has an axis of rotation. The tire includes two inextensible annular bead structures for attachment to a vehicle rim, a carcass-like structure having at least one reinforced ply, the carcass-like structure being wound about the two bead structures, a tread disposed radially outward of the carcass-like structure, and a shear band structure disposed radially between the carcass-like structure and the tread. The two bead structures include at least one layer of a lightweight foam material.

Improving endurance of bead of radial tire for heavy vehicle. Tire has two beads (2) contacting rim (3) connected by carcass reinforcement (4) having carcass layer (5), with main part (6) wrapped, in each bead (2), axially from inside towards outside of the tire, around bead wire (7) having diameter (L), to form turnup (8) having free end (E). Each bead (2) has filling element (9) with filling compound (10) and extending radially towards outside from bead wire (7) and axially between turnup (8) and main part (6). The distance (I) between turnup (8) and main part (6) decreases continuously from bead wire (7) as far as a first minimum distance (a) reached at a first point (A) of turnup (8), then increases continuously from the first point (A) of turnup (8) as far as a first maximum distance (b) reached at a second point (B) of turnup (8).

The run-flat tire of this disclosure includes a tread portion, a pair of sidewall portions, bead portions, side reinforcing rubbers with crescent-like cross section, and a carcass formed of plies of radially arranged cords, wherein: when the tire is mounted to a rim, and an internal pressure of 250 kPa or more is applied to the tire, in a case where a sectional width SW of the tire is less than 165 mm, a ratio of the sectional width SW to an outer diameter OD of the tire, SW/OD, is 0.26 or less; in a case where the sectional width SW of the tire is 165 mm or more, the sectional width SW and the outer diameter OD of the tire satisfy a relation expression OD≧2.135×SW+282.3 (mm); and the relation expression 0.5≦WG/WB≦0.8 is satisfied.

The run-flat tire of this disclosure includes a tread portion, a pair of sidewall portions, bead portions, side reinforcing rubbers with crescent-like cross section, a carcass formed of plies of radially arranged cords, wherein: when the tire is mounted to a rim, and an internal pressure of 250 kPa or more is applied to the tire, in a case where a sectional width SW of the tire is less than 165 mm, a ratio of the sectional width SW to an outer diameter OD of the tire, SW/OD, is 0.26 or less; in a case where the sectional width SW of the tire is 165 mm or more, the sectional width SW and the outer diameter OD of the tire satisfy a relation expression OD≧2.135×SW+282.3 (mm); the bead portions have bead cores, and further have bead fillers; and the relation expression 1.8≦H1/H2≦3.5 is satisfied.

In a pneumatic tire (1) that achieves both ride comfort and steering stability at a high level, a bead core (5) has a ratio of the maximum width of the core to the height of the core of 0.8 or less in a cross-section in the tire width direction. A cord (9) is provided in at least one part from a bead portion (2) to a sidewall portion (3) at an angle of 0 to 10° with respect to the circumferential direction. The cord (9) has an inflection point in a stress-strain curve, with a low elastic modulus in a low-strain region at or below the inflection point, and a high elastic modulus in a high-strain region above the inflection point.

Assembly comprising a tire and a mounting rim, the tire comprising two beads each comprising at least one annular reinforcing structure and a carcass reinforcement anchored in the two beads by a turn-up, each bead comprising a filler of a rubber composition extending radially a radial distance DBE from the radially innermost point of the annular reinforcing structure, DBE being less than or equal to 10% of the radial height H of the tire, at least one sidewall further comprising a stiffening reinforcement of metallic reinforcing elements oriented at an angle less than or equal to 10 degrees to the circumferential direction, and positioned such that the distance DAE between the radially innermost point of the annular reinforcing structure and the radially outer end of the stiffening reinforcement is greater than or equal to 20% and less than or equal to 40% of H and that the distance DAI between the radially inner point of the annular reinforcing structure and the radially inner end of the stiffening reinforcement is less than or equal to 20% of H.

A run-flat tire includes a side reinforcing rubber layer, a first bead filler on an inner side of a carcass turned-up portion in a width direction, and a second bead filler on an outer side of the carcass turned-up portion in the width direction. A first bead filler height is 30% or less of a tire cross-sectional height SH. A second bead filler height is 50% or greater of the height SH. A cross-sectional area of the second bead filler is from 150% to 400% of a cross-sectional area of the first bead filler. A relationship (0.16×SH×LI−1100)≤S.sub.ALL≤(0.16×SH×LI−800) is satisfied, where S.sub.ALL represents a sum of cross-sectional areas of the side reinforcing rubber layer and the first and second bead fillers, and LI represents a load index.

In a pneumatic tire, a carcass layer is between bead portions, a bead core is in each bead portion, a reinforcement layer is on an outer side of the carcass layer, and a tread rubber layer is on the outer side of the reinforcement layer. A pair of first boundary lines passes through an intersection of an extension of a side arc forming a tread profile and an extension of a shoulder arc and orthogonal to a tire inner surface, a pair of second boundary lines passes through a rim check line and orthogonal to the tire inner surface, first to third regions are defined which have cross sectional areas of SA, SB, and SC, respectively, and the first to third regions respectively have lengths of a, b, and c along the tire inner surface such that 7.5≤SA/a≤11.5 and 2.0≤SB/b≤6.0 are satisfied.

A pneumatic tire comprises a carcass ply extending between bead portions through a tread portion and sidewall portions, and turned up around a bead core from the inside to the outside of the tire in each of the bead portions, so as to form a pair of turnup portions and a main portion therebetween. In each the bead portion, a first apex rubber and a second apex rubber are disposed. The first apex rubber is disposed between the turnup portion and the main portion. The second apex rubber is disposed axially outside the turnup portion. A complex elastic modulus b of the second apex rubber is larger than that of the first apex rubber. The cross-sectional width Wt in mm of the tire and the outer diameter Dt in mm of the tire satisfy the following conditions Dt=<59.078×Wt.sup.0.498 and Dt>=59.078×Wt.sup.0.460.