A pneumatic tire includes stud pins inserted into holes disposed in the tire surface. The stud pins each include a body portion and a flange disposed closer to the bottom side of each of the holes than the body portion and having an outer diameter larger than the body portion. The holes each include a securing portion coming into contact with the outer peripheral surface of the body portion of the stud pin to secure the stud pin and an enlarged diameter portion disposed closer to the bottom wall side of the hole than the securing portion, having an inner diameter larger than the securing portion, and coming into contact with the outer peripheral surface of the flange of the stud pin to secure the stud pin. The side wall of the enlarged diameter portion is provided with a protrusion protruding toward the interior of the hole.

A tyre comprises a tread portion comprising a first tread edge and a second tread edge, and the tread portion is provided with a plurality of oblique grooves. The plurality of the oblique grooves includes a first oblique groove and a second oblique groove. Each of the first oblique grooves and the second oblique grooves has an open end and a terminating end, and a first steeply-inclined portion positioned on a side of the open end, a second steeply-inclined portion positioned on a side of the terminating end, and a mildly-inclined portion positioned between them. The second steeply-inclined portion includes a part in which an angle thereof with respect to a tyre circumferential direction is gradually decreased as it goes toward the terminating end.

Provided is a tire for winter of which on-snow performance can be improved without compromising anti-wandering performance. A tire for winter comprises a tread part The tread part is provided with: a plurality of first inclined major grooves extending at an incline from one tread end beyond a tire equator and ending without reaching another tread end; first inclined minor grooves provided between the first inclined major grooves; a plurality of second inclined major grooves extending at an incline from the other tread end, in a direction opposite the first inclined major grooves, beyond the tire equator and ending without reaching the one tread end; second inclined minor grooves provided between the second inclined major grooves; a plurality of first longitudinal grooves dividing first land parts; and a plurality of second longitudinal grooves dividing second land parts.

A stud pin fitted into a tread portion of a pneumatic tire comprises a buried base portion extending in a direction, the buried base portion securing the stud pin in the tread portion by being pressed by a side surface of the stud pin installation hole upon the stud pin being embedded in the stud pin installation hole, and a tip portion connected to an end portion of the buried base portion in the extending direction, the tip portion protruding past the tread portion and coming into contact with a road surface upon the buried base portion being embedded in the stud pin installation hole. A connection portion of the tip portion with the buried base portion has a cross-sectional area in a plane orthogonal to the extending direction of the buried base portion greater than an area of the tip end surface.

A method for arranging stud pins in a pneumatic tire is a method for arranging stud pins in a tread portion at intervals in a tire width direction so as to form a plurality of rows. This method includes specifying an inner region, an intermediate region, and an outer region by virtually partitioning the tread portion into equal three parts from a center line extending in a tire circumferential direction to a ground contact end in the tire width direction outward. The method also includes arranging the stud pins such that among numbers of stud pins per row in the inner region, the intermediate region, and the outer region, the number in the outer region is the largest, the number in the intermediate region is the second largest, the number in intermediate region is the smallest.

A pneumatic tire includes a shoulder block on an outer side in the tire width direction. The pneumatic tire includes an edge portion protruding from an end portion of the shoulder block located on the outer side in the tire width direction toward a tire step-in side so as to be inclined toward the center side in the tire width direction.

A pneumatic tire includes a center rib extending in a tire circumferential direction at a center in a tire width direction; a plurality of inclined blocks branching and extending from the center rib to both sides in the tire width direction and defined by a plurality of inclined grooves extending obliquely in the tire circumferential direction toward an outside in the tire width direction; and a plurality of stud pins arranged in at least one of inclined blocks, in which the plurality of inclined grooves are arranged at predetermined formation intervals in the tire circumferential direction so as not to intersect with each other, and a length of each inclined groove in the tire circumferential direction is within twice the formation intervals.

A tread portion has a pin hole with a stud pin being mounted. In the periphery of the pin hole a recess is formed that gradually deepens as the recess extends toward radially outside and that has a depth of 10% or less of the depth of the pin hole.

A pneumatic tire includes a plurality of blocks formed by being divided by a longitudinal groove in a tire width direction and divided by a lateral groove in a tire circumferential direction. The blocks include a first block on the inner side in the tire width direction, a second block on the outer side in the tire width direction, a third block adjacent to the first block in the tire circumferential direction, and a fourth block adjacent to the second block in the tire circumferential direction. The pneumatic tire includes a bridge formed in the longitudinal groove and the lateral groove and coupling the first block, the second block, and the third block, or the third block, the fourth block, and the second block.

A winter tire includes a tread portion with a designated rotational direction. The tread portion is provided with at least one central block on a tire equator. The central block includes a first tapered portion. The first tapered portion includes an axial width gradually decreasing toward the rotational direction and a leading edge extending along an axial direction of the tire. The first tapered portion is provided with a hole for installing a stud pin.