A ground contact region of the tread portion of a studdable tire includes a center region located over a range corresponding to a length of 5 to 25% of a ground contact width from a tire centerline on each of both sides of the tire centerline in a tire width direction; and two shoulder regions located on both sides of the center region in the tire width direction. In each of the center region and the shoulder regions, a plurality of the stud pin installation holes are disposed along each of four or more pin arrangement lines extending in a tire circumferential direction. An average value of adjacent intervals between the pin arrangement lines in the center region is larger than an average value of adjacent intervals between the pin arrangement lines in each of the shoulder regions.

A tire for running on rough terrain comprises a tread portion 2 bound with an intended tire rotational direction. The tread portion 2 comprises a row of crown blocks 10 and rows of middle blocks 11. The crown blocks 10 and the middle blocks 11 each has an axially-elongated shape. A crown front edge 15 of each of the crown block 10 comprises a most concave portion 18 positioned at the most toe-side thereof in the tire rotational direction and a pair of inclined edges 20 extending from the most concave portion 18 toward axially both sides thereof and toward the heel-side in the tire rotational direction. The inclined edges 20 are each inclined at an angle from 10 to 45 degrees with respect to the tire axial direction. A middle front edge 21 of each of the middle blocks 11 extends axially outwardly and is inclined to the heel-side.

Tread (10) for agricultural tire (1) comprising a plurality of lugs protruding from the ground of the tread (11) in radially outer direction extending at a given inclination angle from a central portion of the tread toward both axial ends of the tread and alternately arranged at given intervals in the circumferential direction on one side and on the other with respect to the equatorial plane of the tire. The lugs (2) comprising a stepping-in surface (21) wherein the stepping-in surface (21) of at least one lug (2) comprises on its sidewall a first radially outer, concave surface (211) and a second, radially inner, concave surface (212) intersecting each other in a transition point (D) when viewed in a circumferential section.

A tire for running on rough terrain for which an intended tire rotational direction is specified, comprises: a tread portion 2 provided with a first block 11 having a ground contacting top surface 16, and a base cross sectional shape 17. The ground contacting top surface 16 has a polygonal shape having a heel-side oblique edge 21 inclined with respect to the tire axial direction. The base cross sectional shape 17 is a polygon having a heel-side axial edge 22 extending in the tire axial direction. In the top view of the first block, an angle a formed between the heel-side oblique edge 21 and the heel-side axial edge 22 is in a range from 5 to 45 degrees.

A non-pneumatic tire (10) comprising a tread band having a ground engaging surface, a first reinforcement layer (250) comprised of at least one reinforcement (251) oriented in the tire's circumferential direction, a second reinforcement layer (254), located radially outward from said first reinforcement layer (250), said second reinforcement layer (254) comprised of a plurality of reinforcements oriented at an angle in a first direction to said tire's circumferential direction, a third reinforcement layer (258), located radially outward from said second reinforcement layer (254), said third reinforcement layer (258) comprised of a plurality of reinforcements oriented at an angle in a second direction to said tire's circumferential direction and a fourth reinforcement layer (262), located radially outward from said third reinforcement layer (258), comprised of at least one reinforcement oriented in the tire's circumferential direction.

Provided is a pneumatic tire including center main grooves, shoulder main grooves, a center land portion, middle land portions, shoulder land portions, and lug grooves provided in each shoulder land portion. The pitch of the lug grooves is changed on the tire circumference. The profile line L1 that defines the road contact surface of the center land portion protrudes further to the outer side in the tire radial direction than the standard profile line L0. The profile line L2 that defines the road contact surface of the middle land portion and the shoulder land portion protrudes further to the outer side in the tire radial direction than the standard profile line L0. The ratio of the groove volume of the lug grooves to the size of the pitch of the lug grooves in the shoulder land portion decreases as the pitch increases, and increases as the pitch decreases.

A tire comprises a tread portion 2 provided with a first main groove 3 and a second main groove 4 each extending in a zigzag manner and a land region 10 defined between them. The land region 10 is provided with a longitudinal sipe 15 extending in a zigzag manner in the tire circumferential direction, first lug grooves 16, and second lug grooves 17. The land region 10 comprises first blocks 21 divided by the longitudinal sipe 15 and the first lug grooves 16, and second blocks 22 divided by the longitudinal sipe 15 and the second lug grooves 17. Each of the first blocks 21 and the second blocks 22 is provided with not less than three transverse sipes 25 extending across the entire width of the each of the first blocks 21 and the second blocks 22.

Tread of a tire for an agricultural vehicle having each lug (3) extending over a radial height H in a radial direction (ZZ) from a bottom surface (5) to a contact face (6), extending over an axial width L in an axial direction (YY) from an axially inner end face (7) to an axially outer end face (8), and extending over a mean thickness E in the circumferential direction (XX) from a trailing face (9) to a leading face (10). The leading face (10) of each lug (3) comprises a discontinuity (11) that extends circumferentially in the direction of the trailing face (9), axially inwards from the axially outer end face (8) and radially inwards from the contact face (6). The discontinuity (11) on the leading face (10) of each lug (3) is continued by a recess (12) formed in the bottom surface (5).

A tyre for vehicle wheels having a tread pattern includes: a) two circumferential grooves, which define a first and a second shoulder region, and one central region; b) a plurality of asymmetric transverse grooves having a substantially V shape, which extend for the whole width of the tread, including an alternate sequence of a first and a second asymmetric transverse groove defining an alternate sequence of a first and a second asymmetric module; and c) a plurality of lateral transverse grooves, which includes one first lateral transverse groove extending for the whole width of the first shoulder region and for a portion of the central region of the first asymmetric modules, and one second lateral transverse groove extending for the whole width of the second shoulder region and for a portion of the central region of the second asymmetric modules.

Tire (1) for an agricultural vehicle, and more particularly the tread (2) thereof, has improved traction in the field, while reducing the sensitivity of the lugs (3) to attack by stubble. Each lug (3) comprises first lug portion (31), having height H1, and second lug portion (32), having height H2 and having a mean angle of inclination A2 with respect to circumferential direction (XX) of the tire. The first lug portion (31) is comprised of a radial superposition of N layers C1.sub.i (33), where i varies from 1 to N, each having a height H1.sub.i, each layer C1.sub.i having a mean angle of inclination A1.sub.i strictly less than the mean angle of inclination A2, and, when N is strictly greater than 1, the angle A1.sub.j relative to a layer C1.sub.j, where j varies from 1 to N1, is strictly less than the angle A1.sub.j+1 relative to the layer C1.sub.j+1.