The ratio of the width of the chip splitting groove to the width of the tip, the width of the chip splitting groove, and the ratio of the depth of the chip splitting groove to the width of the tip are optimized.

A first score line (430) is provided with a modified groove width portion (435) in which the groove width differs from the groove width of other portions.

Each of the side regions has a groove width expanding toward a circumferential groove.

The ratio of the groove width (N) to the tooth width (S) is between 0.5 and 3.0.

The width (W3) of the protruding part (13) in a direction perpendicular to a groove center line (G1) of the major groove (3) is 50% to 100% of the groove width (W1) of the major groove (3).

A second ramiform groove (42) has a length which is 40% - 90% of the length of the first ramiform groove and has a groove width which is not narrower than the width of the first ramiform groove.

The process for increasing or decreasing groove width may be repeated any number of times as necessary to achieve a proper groove width.

The groove width (N) is at least 0.8 mm.

The first recording region (R1) has a track pitch tp1, groove width w1, and a groove depth d1 and the second recording region (R2) has a track pitch tp2, a groove width w2, and a groove depth d2.

The narrow inclination groove (44) has a groove width set in the range of 0.3-2.5 mm.

The wide groove width sections (80A) and the narrow groove width sections (80B) are alternately provided along the peripheral direction of the tire.

The groove width of the peripheral groove (3) along the widthwise direction of the tread changes in a predetermined repeated cycle along the direction of the perimeter of the tire.

A first ramiform groove (41) has a length which is 40% or more of the tread surface length and a groove width which is 10% - 25% of the width of a circumferential groove.

The peripheral-direction minute groove extends in the peripheral direction of the tire, and has a narrower groove width than that of the shoulder lag groove.

The anvil surface includes a plurality of angled grooves having a variable groove width.