Sumitomo Rubber Industries Limited

Kenji Hamamura

Tatsuhiro Tanaka

Takahiro Kawachi

Subaru Toya

Keiji Takagi

Hiroki Kawai

Masako Nakatani

Suguru Izumo

Ayuko Yamada

Natsuki Maekawa

Noboru Okabe

Daichi Fujii

A pneumatic tire having a side portion and a clinch portion, wherein: in a meridian cross section, the distance from a bead baseline to the outside portion in the width direction of the clinch portion is greater than the distance to the inside portion in the width direction; the E*of the side portion, as measured at 70° C., a frequency of 10 Hz, an initial distortion of 5%, and a distortion rate of 1%, is less than the E*of the clinch portion; and, formulas (1) and (2) are satisfied:1600≤(×π/4)/≤2827.4  (1)[(+1.5×10)/]≤2.88×10  (2)where Wt is the cross-sectional width of the tire installed on a standardized rim and filled with air to an internal pressure of 250 kPa, Dt is the outer diameter, and V is the volume of the tire.

Pneumatic tire

The present invention provides a pneumatic tire which is sufficiently reduced in the rolling resistance during high-speed travel, while having sufficiently improved chipping resistance. A pneumatic tire which has a tread part, wherein: at least one rubber layer that forms the tread part contains a rubber component that contains an isoprene rubber, a styrene butadiene rubber and a butadiene rubber, while containing more than 5 parts by mass but 25 parts by mass or less of carbon black relative to 100 parts by mass of the rubber component; and if Wt (mm) is the cross-sectional width of the tire, Dt (mm) is the outer diameter of the tire, and V (mm) is the virtual volume that is the volume of the space occupied by the tire when this pneumatic tire is installed on a standardized rim and the internal pressure is 250 kPa, (formula 1) and (formula 2) are satisfied.1700≤(Dt×π/4)/Wt≤2827.4  (formula 1)[(V+1.5×10)/Wt]≤2.88×10  (formula 2)

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.

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)

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Hyogo, Japan

Kenji Hamamura