Patent ID: 9409445
Filing Date: 2016-08-09
CPC Classification: B60C

Claim Text:
1. A heavy duty pneumatic tire comprising: a tread portion provided with two shoulder main grooves extending in the tire circumferential direction and each having a width in a range of from 5 to 13 mm, shoulder blocks arranged axially outside each of the shoulder main grooves, and crown blocks arranged between the two shoulder main grooves, each of said crown blocks provided with sipes extending axially across the entire width thereof the sipes being two parallel sipes each having a zigzag shape made up of three segments, whereby the crown block is circumferentially subdivided into a pair of outside block pieces and one inside block piece therebetween, wherein the outside block pieces are each provided with small holes in a single axial row, while the inside block piece is provided with no hole, each of the small holes extends radially inwardly from a ground contacting top surface of the holed block piece to its bottom at a depth in a range of from 30 to 100% of a depth of the shoulder main grooves, a total opening area of said small holes in the ground contacting top surface of each holed block piece is in a range of from 2 to 12% of the overall area of the ground contacting top surface, said shoulder blocks are a row of axially inside shoulder blocks, a row of axially outside shoulder blocks, and a row of middle shoulder blocks therebetween, each of the axially inside shoulder blocks is provided in the ground contacting top surface thereof with two sipes extending axially across the entire width thereof so that the axially inside shoulder block is subdivided into a pair of outside block pieces and one inside block piece therebetween, the outside block pieces are each provided with a single zigzag sipe, while the inside block piece is provided with no sipe, each of the middle shoulder blocks is provided in the ground contacting top surface thereof with a single sipe extending axially across the entire width thereof so that the middle shoulder block is subdivided into a pair of block pieces, and the inside shoulder blocks, the middle shoulder blocks and the outside shoulder blocks are provided with no holes.