In a pneumatic tire, a bead filler is radially outward of a bead core, a carcass turned up end is radially inward of an outer side end of the bead filler, the turned up end is spaced from a carcass body, a reinforcement layer is laterally outward of the bead filler, a sidewall rubber extends from a sidewall to the bead, an inner rubber reinforcing layer is between the bead filler and the reinforcement layer and adjacent to the turned up end, a crack suppression layer is between the reinforcement layer and the sidewall rubber, the crack suppression layer extends 5 mm or more from where the crack suppression layer overlaps, the reinforcement layer contacts the carcass body radially outwardly of the bead filler, and a 100% modulus Kc.sub.M100 of the crack suppression layer is at least 1.5 times that of the sidewall rubber.

In a pneumatic tire mountable on a 5°-tapered rim, a bottom of a bead core is inclined from 0°-5° in a direction in which the bottom diverges toward an outer side in a radial direction as the bottom extends from an inner side in the width direction toward an outer side in the width direction. Each bead portion includes a base, a toe, and a heel. The base is inclined from 8°-12° in a direction in which the bead base portion diverges toward the outer side in the radial direction as the base extends from the inner side toward the outer side in the width direction. The heel has a radius of curvature from 25-30 mm. A rim cushion rubber has a modulus at 100% elongation within a range from 5.0-8.0 MPa. The toe has a displacement between before and after mounting on the rim from 9.0-13.5 mm.

A tire includes: a bead core; a bead filler which extends to an outer side in the tire-radial direction of the bead core; a carcass ply which extends from the bead core to another bead core, and folded back around the bead core; a first rubber sheet which covers a folding end of the carcass ply folded back from an inner side in the tire-width direction; and a second rubber sheet which covers the folding end of the carcass ply folded back from an outer side in the tire-width direction, in which an electronic component is provided between the first rubber sheet and the second rubber sheet.

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.

This invention relates to pneumatic radial tires which exhibit improved rolling resistance (provide better fuel economy) and improved performance characteristics. More particularly, this invention relates to the structure of radial ply tires for heavy load vehicles such as trucks, buses, and the like. It is based upon that finding that a defined profile of the outer surface of the sidewall portion can lead to a tire with reduced rolling resistance and a reduced generation of heat. The reduction in rolling resistance is obtained by a specific shaping of the bead portion of the tire which allows a bead mass reduction with an acceptable trade-off with regard to bead durability.

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.

Of layers configuring a bead core of a pneumatic tire, the width W0 of one of the layers including the greatest number of rows, the width W1, W2 of other of the layers located respectively innermost and outermost in the radial direction satisfy W1>W2 and W2≤0.5×W0. The position of width W0 is inward in the radial direction of the center of the bead core. A carcass is folded and curved along the bead core and extends toward sidewalls where a folded back portion of the carcass contacts a body of the carcass. A rubber occupancy ratio in a closed region formed by the body and the folded back portion is 0.1% to 15%. The cross-sectional area S2 and hardness H2 of a filler outward of the carcass in the lateral direction, and the cross-sectional area S1 and the hardness H1 of the side reinforcing layer satisfy 0.12≤(S2×H2)/(S1×H1)≤0.50.

A pneumatic tire includes a pair of bead cores; a pair of bead fillers that are connected to the pair of bead cores; a carcass ply that is suspended between the pair of bead cores; a side wall rubber that is arranged on a tire-outer-surface-side of the carcass ply and constitutes a tire outer surface; a chafer layer that is turned from a tire-inner-surface-side to the tire-outer-surface-side around the bead cores and the bead fillers and rolled up on an outer surface of the carcass ply; and a pair of support rubbers that are located between the side wall rubber and the carcass ply and arranged so as to hold a rolled-up end of the chafer layer from both sides in a tire width direction. A modulus values of the pair of support rubbers are higher than a modulus value of the side wall rubber.

Provided is a pneumatic tire with which the same driving safety as prior arts can be ensured and an improvement in fuel efficiency performance and durability performance is achieved. In this pneumatic tire, the tire radial direction outside end section of a chafer is disposed on the tire surface part, the loss tangent tan δ70° C.-SW of a side wall, the loss tangent tan δ70° C.-C of the chafer, complex elastic modulus E*70° C.-SW of the side wall, and the complex elastic modulus E*70° C.-C of the chafer under the condition of 70° C., an elongation of 1%, and a frequency of 10 Hz, and the loss tangent tan δ150° C.-SW of the side wall, and the loss tangent tan δ150° C.-C of the chafer measured under the condition of 150° C., an elongation of 1%, a frequency of 10 Hz satisfy the following expression. tan δ70° C.-SW+tan δ70° C.-C≤0.25|tan δ70° C.-SW−tan δ70° C.-C|≤0.07 E*70° C.-C−E*70° C.-SW≤6.5 MPa tan δ150° C.-SW+tan δ150° C.-C≤0.20

A pneumatic tire includes a pair of bead cores; a pair of bead fillers; a carcass ply; a side wall rubber; a chafer layer that is rolled up on an outer surface of the carcass ply; and a pair of support rubbers that is located between the side wall rubber and the carcass ply and arranged such that a rolled-up end of the chafer layer is sandwiched from both sides in a tire width direction. The pair of support rubbers includes a tape rubber located inside in the tire width direction and a rear pad rubber located outside in the tire width direction. A modulus value of the tape rubber is higher than a modulus value of the side wall rubber. A modulus value of the rear pad rubber is higher than the modulus value of the tape rubber.