US Patent 7669624 Pneumatic tire with tread having circumferential grooves

A pneumatic tire includes a tread surface on which a plurality of circumferential groove portions is formed. From among circumferential groove portions, a circumferential groove portion situated closest to a shoulder portion side in a tire width direction has a center of a groove-bottom innermost portion at a portion where a groove width in at least a tire circumferential direction is the narrowest, positioned closer to an equatorial surface in the tire width direction than a center of the groove width. An angle between a virtual extension portion of the tread surface and a groove wall on the equatorial surface side is equal to or less than an angle between the virtual extension portion of the tread surface and a groove wall on the shoulder portion side.