Patent ID: 6626215
Filing Date: 2003-09-30
Classification: B60C,Y10S

Abstract:
A pneumatic tire comprising:a tread portion provided on each side of the tire equator with two axially inner circumferential grooves, two axially outer circumferential grooves and a plurality of oblique grooves, each of the axially inner and outer circumferential grooves extending substantially straight in the tire circumferential direction to define at least one substantially straight circumferential rib between the inner two circumferential grooves, and the oblique grooves extending between the inner and outer circumferential grooves to define narrow and circumferentially long blocks therebetween, said oblique grooves inclined at angles &thgr; of not more than 60 degrees with respect to the circumferential direction of the tire, the angle &thgr; of each of the oblique grooves gradually increasing from an axially inner to an axially outer end thereof, each of said long and narrow blocks being provided with at least two sipes each extending across the block from one of the oblique grooves to an adjacent one of the oblique grooves, while inclining reversely to the oblique grooves, to subdivide the block into at least three block pieces including an axially innermost block piece, and axially outermost block piece, and at least one middle block piece therebetween, and top surface areas of said at least three block pieces gradually increasing from the axially innermost block piece to the axially outermost block.