Patent ID: 7581574

Claim:
A pneumatic tire comprising a tread portion having a tread width and provided with at least two circumferentially continuously extending main grooves to axially divide the tread portion into at least three annular regions each provided with axial grooves each extending from one of the axial edges of the annular region, wherein each said axial groove is defined as having a groove width of from 2.0 to 6.0 mm and an axial length of not less than 40% of the axial width of the annular region, said at least three annular regions are different from each other with respect to the number Nj of the axial grooves therein, and the greatest common divisor of the different numbers Nj of said at least three grooved annular regions is in a range of from 10 to 40, and wherein the tread portion is provided with a tread pattern formed by circumferentially repeating a pattern unit a number M times, the pattern unit extends across the entire tread width and includes some of the axial grooves in said at least three annular regions, and within the pattern unit, the number Tj of the axial groove or grooves in each of the annular regions is varied between the annular regions having the different numbers Nj, and said number M is equal to said greatest common divisor.