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).

Each of at least two layers of a carcass reinforcement has a breaking force per unit width higher than 2250 daN/dm. The minimum strength per unit width, measured for an elongation of less than 10%, of a second layer of carcass reinforcement is strictly greater than a value equal to 20% of the minimum strength per unit width, measured for an elongation of less than 10%, of a first layer of carcass reinforcement. The reinforcing elements of the two layers of carcass reinforcement have a thread count of less than 750 tex. The elongation of the reinforcing elements of the second layer of carcass reinforcement is greater than 4% under a force of 20 daN, and the secant elastic modulus values under tension at 10% elongation, Mt, Mj, satisfy the relationship Mt/Mj≧1.

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.

In the tire 2, fillers 10 are layered over clinches 8 in portions outward of a carcass 14 in the axial direction. A carcass ply 50 is turned up around cores 44. Turned-up portions 50a are disposed between the fillers 10 and apexes 46. Each clinch 8 has a maximum thickness Tcx that is measured along a line normal to an inner surface, in the axial direction, of the clinch 8. A ratio of a thickness Tf1 of the filler 10 to a sum of the thickness Tf1 and the thickness Tcx is greater than or equal to 0.1 and not greater than 0.6. A percentage of a complex elastic modulus E*f of the filler 10 relative to a complex elastic modulus E*a of the apex 46 is greater than or equal to 70% and not greater than 125%.

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 tire includes: a tire frame member formed in a ring shape from a frame resin material, and including a pair of bead sections, a pair of side sections, and a crown section; a ring shaped bead core that is embedded in and joined to each of the bead sections, and that is formed by a single strand, or plurality of strands, of bead cord extending in the tire circumferential direction, and covered with, and joined to, a covering resin material; and an extension portion that extends from each of the bead cores in a direction that intersects with the tire circumferential direction when viewed from a tire side face, and that is joined to the tire frame member.

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.

A pneumatic tire comprises: a tread portion; a pair of sidewall portions; a pair of bead portions each with a bead core embedded therein; a toroidal carcass extending between the bead portions; and a sidewall rubber disposed axially outside the carcass in each of the sidewall portions. The bead portion has a bead bottom surface which contacts with a bead seat of a wheel rim when the tire is mounted thereon. The bead bottom surface comprises an axially inner region including a bead toe and an axially outer region including a bead heel. The axially inner region is formed by a canvas chafer. The axially outer region is formed by the sidewall rubber extended radially inwardly from the sidewall portion.

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 having a tread, a sidewall, a bead portion having a bead core, a bead reinforcing layer reinforcing the bead portion, and a carcass ply moored on a bead core of the bead portion, wherein the bead reinforcing layer and adjacent members adjacent to the bead reinforcing layer are each composed of a rubber composition containing an amine type antioxidant, 0.3 to 8 parts by mass of the amine type antioxidant is contained in the bead reinforcing layer based on 100 parts by mass of the rubber component, and the adjacent member adjacent to the bead reinforcing layer and the bead reinforcing layer satisfy the following formula:
2≤B/A≤8
A: Content (wt %) of amine type antioxidant in bead reinforcing layer.
B: Content (wt %) of amine type antioxidant in the adjacent member.