Patent ID: 8042584

Claim:
A pneumatic tire comprising a tread portion provided with a circumferential groove extending continuously in the tire circumferential direction and having a pair of oppositely opposed groove walls, said circumferential groove provided in at least one of the groove walls with radial grooves arranged along the longitudinal direction of the circumferential groove, each said radial groove having a radially outer end positioned in a range (a 1 ) of from 0 to 20% of the depth (GDt) of the circumferential groove, and a radially inner end positioned in a range (a 2 ) of from 80 to 100% of the depth CGDt) of the circumferential groove, and the radial groove having an opening width (g) of not less than 1.0 mm, but not more than 6.0 mm, wherein the tread portion is provided in its central zone with a central circumferential groove extending continuously in the tire circumferential direction, not provided with said radial grooves, and further the tread portion is provided with axial grooves on each side of the circumferential groove which is provided with the radial grooves, said axial grooves are provided with shutoff wall extending from the groove bottom to the groove top and having a thickness of 0.75 to 1.30% of the tread width (TW), said axial grooves provided with the shutoff walls extend between the central circumferential groove and the axially outer circumferential groove disposed on each side of the central circumferential groove, and between the central circumferential groove and the axially outer circumferential groove, axial grooves without the shutoff walls are further provided alternately with said axial grooves provided with the shutoff walls.