A pneumatic tire comprises a tread portion provided with at least one wide circumferential
groove, the wide circumferential groove extending continuously in the tire circumferential
direction and having a groove width GW of not less than 5% of the ground contacting
width TW, the wide circumferential groove provided in the groove bottom with a
groove bottom rib, the groove bottom rib extending continuously along the overall
length of the wide circumferential groove, the groove bottom rib having a height
Hr in a range of from 0.5 to 3.0 mm and a base width Wr in a range of from 10 to
30% of the groove width GW, and the groove bottom rib provided in the top face
with a small groove having a depth Dr of less than the height Hr.
