Pneumatic tire

A pneumatic tire comprising a tread surface which, when viewed as a meridian cross-section, is formed having a profile with a plurality of differing curvature radii, wherein:

• in a state where the pneumatic tire is assembled on a regular rim and is inflated to an inner pressure that is 5% of a regular inner pressure, when a curvature radius of a center portion arc located on a centermost side in a tire width direction of the tread surface is defined as TR1, a contour range that is a width from an equatorial plane to an end of the center portion arc in the tire width direction is defined as L1, a tread developed width that is a width of the tread surface in the tire width direction is defined as TDW, and an external tire diameter that is a diameter of a portion of the tread surface in a tire radial direction having a largest diameter is defined as OD,
• K1, as derived from the contour range L1 and the developed tread width TDW in formula (1) below, satisfies 0.6<K1≦0.9,
• K2, as derived from the curvature radius TR1 of the center portion arc and the external tire diameter OD in formula (2) below, satisfies 2.0<K2:
• K1=L1/(TDW×0.5) (1)
• K2=TR1/OD (2),
• the tread portion is formed from tread portion rubber comprising a cap tread forming the tread surface and an under tread located inward of the cap tread in the tire radial direction;
• wherein the under tread is formed from an inner side under tread located on an inner side in the tire width direction and an outer side under tread that is continuous with the inner side under tread and is located on an outer side in the tire width direction;
• when a width from the equatorial plane to an end of the inner side under tread in the tire width direction is defined as LB, KB, as derived from the width LB and the developed tread width TDW in formula (4) below, satisfies 0.9K1≦KB≦1.1K1;
• and
• a JIS A hardness of the inner side under tread at room temperature is 55 or greater but 65 or less, and a JIS A hardness of the outer side under tread at room temperature is 3 or greater but 15 or less lower than the JIS A hardness of the inner side under tread at room temperature:
• KB=LB/(TDW×0.5) (4).

A pneumatic tire comprising a tread surface which, when viewed as a meridian cross-section, is formed having a profile with a plurality of differing curvature radii, wherein:

• in a state where the pneumatic tire is assembled on a regular rim and is inflated to an inner pressure that is 5% of a regular inner pressure, when a curvature radius of a center portion arc located on a centermost side in a tire width direction of the tread surface is defined as TR1, a contour range that is a width from an equatorial plane to an end of the center portion arc in the tire width direction is defined as L1, a tread developed width that is a width of the tread surface in the tire width direction is defined as TDW, and an external tire diameter that is a diameter of a portion of the tread surface in a tire radial direction having a largest diameter is defined as OD,
• K1, as derived from the contour range L1 and the developed tread width TDW in formula (1) below, satisfies 0.6<K1<0.9,
• K2, as derived from the curvature radius TR1 of the center portion arc and the external tire diameter OD in formula (2) below, satisfies 2.0<K2:
• K1=L1/(TDW×0.5) (1)
• K2=TR1/OD (2), and
• a tread portion is formed from tread portion rubber comprising a cap tread forming the tread surface and an under tread located inward of the cap tread in the tire radial direction;
• and wherein the cap tread is formed from an inner side cap tread located on an inner side in the tire width direction and an outer side cap tread that is continuous with the inner side cap tread and is located on an outer side in the tire width direction.