Heavy duty tire including wide main grooves, narrow grooves and lug grooves

摘要

A heavy duty tire is provided in the tread portion with a circumferentially extending main groove on each side of the tire equator, a circumferentially extending narrow groove on each side of each main groove, lug grooves extending from the tread edges to the axially inner narrow grooves, and slits extending between the inner narrow grooves so as to form a rib-like portion between the two inner narrow grooves, first blocks between the inner narrow groove and main groove, second blocks between the main groove and axially outer narrow groove, and third blocks between the outer narrow groove and tread edge; the main grooves are disposed at a distance of 15 to 25% of the tread width from the tire equator; the main groove depth is 10 to 12% of the tread width; the narrow groove depth is less than the main groove depth; and the slit depth is 0.2 to 0.3 time the main groove depth.