Tread for a ribbed pneumatic tire having high density siping zones located in the rib regions

A tread for a ribbed pneumatic tire, the tire tread when on the tire casing comprising at least two circumferentially extending shoulder ribs and at least one center rib wherein each center rib contains two high density siping zones, wherein

• (a) each high density siping zone is circumferentially extending;
• (b) each high density siping zone has an inside edge and an outside edge with a total width between said inside edge and outside edge ranging from about 1.4% to about 4.5% of the overall tread width and said inside edge and outside edge are straight edged and parallel to each other;
• (c) said outside edge of each high intensity siping zone is located from the nearest rib edge by a distance ranging from about 0.2% to about 1.9% of the overall tread width;
• (d) from about 50% to about 80% of the surface area in each high density siping zone is ground contacting with the remaining percent of area being siping;
• (e) no more than 50% of the siping within each high density siping zone is arranged in the circumferential direction;
• and
• (f) at least 75% of all sipes within the high density siping zone is arranged so that their end portions are laterally aligned with, or overlap in the circumferential direction with, an end portion of another sipe with the high density siping zone.