Pneumatic tires having V-shaped directional slant grooves

摘要

In a pneumatic tire having a tread pattern comprised of directional low-slant grooves (1) and directional high-slant grooves (2), tire noise is reduced without adversely affecting tire appearance and production cost by subjecting circumferential length (pitch) of each of the directional low-slant grooves and the directional high-slant grooves to an adequate pitch variation. In particular, the directional low-slant grooves are arranged at 10-20 pitches on the circumference of the tire by using two or more different pitches (Pn) as a pitch variation of the large pitch (P); the directional high-slant grooves are arranged at 3-6 pitches within the large pitch (Pn) by using two or more different pitches (pn) as a pitch variation of the small pitch (p); a pitch ratio of maximum pitch (Pmax) to minimum pitch (Pmin) in the large pitch (Pn) on the full circumference of the tire is 1.05-1.4; and a pitch ratio of maximum pitch (pmax) to minimum pitch (pmin) in the small pitch (pn) within an arbitrary large pitch (Pn) is 1.05-1.6.