TREAD FOR A RIBBED PNEUMATIC TIRE HAVING HIGH DENSITY SIPING ZONES LOCATED IN THE RIB REGIONS

摘要

The present invention relates to a tread for a ribbed pneumatic tire featuring circumferentially extending ribs, at least one of which and preferably all of the ribs contain a high density siping zone. Each high density siping zone is (a) circumferentially extending; and features (b) an inside edge and an outside edge with a total width between the inside edge and outside edge ranging from about 1.4% to about 4.5% of the overall tread width; (c) the outside edge of each high density siping zone being located from the nearest rib edge by a distance ranging from about 0.2% to about 1.9% of the overall tread width; (d) about 50% to about 80% of the surface area in each high density siping zone being ground contacting with the remaining percent of area being siping; (e) no more than 50% of the siping arranged in the circumferential direction; and (f) at least 75% of all sipes within the high density siping zone are arranged so that their end portions are laterally aligned with or overlap in the circumferential direction with an end portion of another sipe within the high density siping zone. When the tread width of the pneumatic tire is for example eight inches (203.2 mm), the total width between the inside edge and outside edge of the high density siping zone ranges from about 3 to 9 mm and the outside edge of each high density siping zone is located from the nearest rib edge by a distance ranging from about 0.5 mm to 4 mm. The high density siping zones reduce rib edge erosion wear by creating a weakened zone without the tendency of tearing.