Sumitomo Rubber Industries Limited

Hiroki Kawai

Dong Miao

Momoka Misaki

Subaru Toya

Kenji Hamamura

A pneumatic tire having a tread, wherein the ground contact surface of the tread is composed of at least two types of rubber compositions different in the thermal conductivity, and the following formulas (1) and (2) are satisfied:1700≤(×π/4)/≤2827.4  (1)[(+1.5×10)/]≤2.88×10  (2)where Wt (mm) is the cross-sectional width and Dt (mm) is the outer diameter of the tire when installed on a standardized rim and inflated to an internal pressure of 250 kPa, and V (mm) is the virtual volume of the space occupied by the tire.

Pneumatic tire

Provided is a pneumatic tire that has reduced rolling resistance during high-speed running as well as excellent durability performance. This pneumatic tire comprises a sidewall and a clinch section in each of a pair of side sections. When the loss tangent of the sidewall is tan δsw and the loss tangent of the clinch section is tan δc when measured under the conditions of 70° C., a frequency of 10 Hz, an initial strain of 5%, and a dynamic strain rate of 1%, then (tan δsw+tan δc)≤0.3 and |tan δsw−tan δc|≤0.07. When the cross-sectional width of the tire is Wt (mm) and the external diameter is Dt (mm) when the pneumatic tire is installed on a standardized rim and internal pressure is set to 250 kPa, and if the volume of space occupied by the tire is a virtual volume V (mm), then (formula 1) and (formula 2) are satisfied.1700≤(×π/4)/≤2827.4  (formula 1)[(+1.5×10)/]≤2.88×10  (formula 2).

Provided is a pneumatic tire for which rolling resistance at high speed running is sufficiently reduced and durability is sufficiently improved. The pneumatic tire has a side portion, a thickness S (mm) of a rubber layer radially outside a carcass on the side portion at the maximum tire width position is 3 mm or less, the loss tangent of the rubber layer measured under the conditions of 70° C., a frequency of 10 Hz, an initial distortion of 5%, and a dynamic distortion rate of 1% is 0.15 or less, and when the cross-sectional width of the tire is Wt (mm) and the outer diameter is Dt (mm) when installed on a regular rim and the internal pressure is 250 kPa, the volume of the space occupied by the tire is the virtual volume V (mm), the following (formula 1) and (formula 2) are satisfied.1700≤(×π/4)/≤2827.4  (formula 1)[(+1.5×10)/]≤2.88×10  (formula 2)

To provide a pneumatic tire excellent in steering stability and fuel efficiency at high-speed driving, it is provided a pneumatic tire having a tread portion with a circumferential groove and a belt layer, wherein a monofilament cord is used as a reinforcing cord for the belt layer; the number of arrangements e (lines/5 cm) of the monofilament cords arranged per 5 cm in the tire width direction in the tire radial cross section of the belt layer is 50/5 cm or more; and the distance G (mm) from the surface of the land portion closest to the equatorial plane among land portions separated by the circumferential groove to the monofilament cord, and the loss tangent (30° C. tan δ) when the rubber composition constituting the surface of the tread portion is measured under conditions of temperature: 30° C., initial strain: 5%, dynamic strain: ±1%, frequency: 10 Hz, and deformation mode: tensile, satisfy 30° C. tan δ×G<1.5.

To provide pneumatic tires with excellent ride quality during high-speed driving, a pneumatic tire having a tread portion with a circumferential groove and a belt layer, wherein a monofilament cord is used as a reinforcing cord for the belt layer; and the number of arrangements e (lines/5 cm) of the monofilament cords per 5 cm in the tire width direction in the tire radial cross section of the belt layer, the distance G (mm) from the surface of the land portion closest to the equatorial plane among land portions separated by the circumferential groove to the monofilament cord, and the loss tangent (30° C. tan δ) when the rubber composition constituting the surface of the tread portion is measured satisfy (30° C. tan δ×G)/e>0.015 is provided.

To provide a pneumatic tire in which both low rolling resistance and improvement of noise performance at high-speed driving are sufficiently achieved, it is provided a pneumatic tire having a tread portion and a belt layer, wherein the tread portion is arranged on the outer side of the belt layer in the tire radial direction, the reinforcing cord in the belt layer is composed of cords made of monofilaments in which 50 lines/5 cm or more of the monofilaments are arranged in the tire width direction in the tire radial cross section of the belt layer, and the maximum load capacity of the tire WL (kg) and the weight of the tire WT (kg) satisfy 0.0145&#x2264;(WT/WL).

To provide a pneumatic tire excellent in steering stability and durability at high-speed driving, it is provided a pneumatic tire having a tread portion and a belt layer, wherein the tread portion is arranged on the outer side of the belt layer in the tire radial direction, the reinforcing cord in the belt layer is composed of cords made of monofilaments in which 50/5 cm or more of the monofilaments are arranged in the tire width direction in the tire radial cross section of the belt layer, and the maximum load capacity of the tire WL (kg) and the weight of the tire WT (kg) satisfy (WT/WL)&#x2264;0.0140.

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Kobe, Japan

Hiroki Kawai