A pneumatic tire, comprising at least sidewall portions and rim guards each provided at the corresponding sidewall portion, wherein: in a cross section in the width direction of the tire assembled with a prescribed rim, an outer contour line, of the rim guard, situated on the outer side in the tire radial direction than the radially outermost peak of the rim guard has an arcuate configuration of which the center of curvature is located on the external side of the tire; radius of curvature R of the outer contour line is in the range of 5 mm≦R≦40 mm; and provided that H represents a distance in the tire radial direction measured from the radially innermost peak to the outermost position in the tire radial direction of a rim flange, 2 mm≦H≦40 mm.

A pneumatic tire mountable on a 15° tapered specified rim includes a bead core, a carcass, a steel cord reinforcing layer, a bead rubber layer, and a first reinforcing rubber layer. A distance from a second line segment to a third line segment is from 4 mm to 12 mm, a complex modulus of the first reinforcing rubber layer is from 6 MPa to 10 MPa, an elongation at break of the first reinforcing rubber layer is from 300% to 450%, a complex modulus of the second reinforcing rubber layer is from 10 MPa to 15 MPa, and a complex modulus of a shock absorbing rubber layer is from 2 MPa to 6 MPa.

A pneumatic tire mountable on a 15° tapered specified rim includes a bead core, a carcass, a steel cord reinforcing layer, a bead rubber layer, and a first reinforcing rubber layer. A distance from a second line segment to a third line segment is from 4 mm to 12 mm, a complex modulus of the first reinforcing rubber layer is from 6 MPa to 10 MPa, an elongation at break of the first reinforcing rubber layer is from 300% to 450%, a complex modulus of the second reinforcing rubber layer is from 10 MPa to 15 MPa, and a complex modulus of a shock absorbing rubber layer is from 2 MPa to 6 MPa.

A pneumatic tire is provided. In a meridian cross-section, an external contour shape of the bead core is a polygon formed by common tangent lines of a plurality of circumferential portions of a bead wire, the external contour shape includes a single vertex located toward the outside in a tire radial direction, an internal angle formed by two sides sandwiching the vertex is an acute angle, a bottom side of the external contour shape is inclined with respect to the tire lateral direction by from 2° to 9°, and the carcass layer is bent and folded back along a circumference of the bead core in a bead portion, a folded back portion of the carcass layer from a position of an outer end of the bead core in the tire radial direction extends toward a sidewall portion in contact with a body portion.

A pneumatic tire is provided. In a meridian cross-section, an external contour shape of the bead core is a polygon formed by common tangent lines of a plurality of circumferential portions of a bead wire, the external contour shape includes a single vertex located toward the outside in a tire radial direction, an internal angle formed by two sides sandwiching the vertex is an acute angle, a bottom side of the external contour shape is inclined with respect to the tire lateral direction by from 2° to 9°, and the carcass layer is bent and folded back along a circumference of the bead core in a bead portion, a folded back portion of the carcass layer from a position of an outer end of the bead core in the tire radial direction extends toward a sidewall portion in contact with a body portion.

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 pneumatic tire has a turned-up carcass ply and a non-turnup carcass ply. The turned-up carcass ply is turned up around bead cores in respective bead portions from the inside to outside of the tire so as to form a pair of turned up portions extending radially outwardly on the axially outsides of the respective bead cores, and a main portion extending between the turned up portions. The non-turnup carcass ply extends between the bead portions and terminates to have edges positioned on the axially outsides of the respective turned up portions. The bead portions are each provided on its outer surface with vent lines protruding therefrom and extending continuously in the tire circumferential direction. The vent lines include a radially outer vent line formed radially outside the edges of the non-turnup carcass ply, and a radially inner vent line formed radially inside the edges of the non-turnup carcass ply.

A pneumatic tire has a turned-up carcass ply and a non-turnup carcass ply. The turned-up carcass ply is turned up around bead cores in respective bead portions from the inside to outside of the tire so as to form a pair of turned up portions extending radially outwardly on the axially outsides of the respective bead cores, and a main portion extending between the turned up portions. The non-turnup carcass ply extends between the bead portions and terminates to have edges positioned on the axially outsides of the respective turned up portions. The bead portions are each provided on its outer surface with vent lines protruding therefrom and extending continuously in the tire circumferential direction. The vent lines include a radially outer vent line formed radially outside the edges of the non-turnup carcass ply, and a radially inner vent line formed radially inside the edges of the non-turnup carcass ply.

A tire capable of showing a sufficient cooling effect on a tire side portion when a vehicle travels at a low speed. A pneumatic tire includes a projection group in a tire side portion. A gap is formed between a first projection and a second projection. A size of the gap in a tire radial direction is smaller than a size of each of the first projection and the second projection in the tire radial direction.

An insert rubber for improving aerodynamics of a tire and an installation method thereof, and provides an insert rubber for improving aerodynamics of a tire and an installation method thereof, in which, by eliminating a space which is located between a bead of a tire and a flange of a rim, airflow is prevented from being introduced between the bead and the flange while a vehicle travels, and the space between the bead and the flange is filled with the insert rubber, thereby preventing turbulence from being generated in the space between the bead and the flange.