Patent ID: 7836926

Claim:
A pneumatic tire having a tread surface having circumferential grooves extending in a circumferential direction of the tire, a rib being defined between the circumferential grooves, the rib including a tread surface section having a center region, end regions and middle regions between the center region and the end regions, a circumferential sipe extending continuously in the circumferential direction of the tire in the center region of the tread surface section, widthwise sipes being disposed in the tread surface section of the rib at prescribed intervals in the circumferential direction of the tire, the widthwise sipes extending in a widthwise direction of the tire in crossing relationship to the circumferential sipe, the widthwise sipes each having opposing terminal ends open to the circumferential grooves, the widthwise sipes each having a widthwise sipe portion in the center region of the tread surface section, widthwise sipe portions in the end regions of the tread surface section and widthwise sipe portions in the middle regions of the tread surface section, the widthwise sipes each having a depth changing in such a manner that the widthwise sipe portions in the center region and end regions of the tread surface section are greater in depth than the widthwise sipe portions in the middle regions of the tread surface section, the circumferential sipe having a depth changing in such a manner that the circumferential sipe is partially shallow between adjacent widthwise sipes, wherein the depth of the circumferential sipe changes periodically in such a manner that a ratio d 1 /d 2 of a minimum depth d 1 thereof to a maximum depth d 2 thereof is 0.1 to 0.5.