A circumferential narrow main groove extending in a circumferential direction in a tread of a pneumatic tire. The circumferential narrow main groove includes a narrow portion opening to a road contact surface of the tread and a widened portion having a wider groove width than the narrow portion. The widened portion is at a groove bottom. A groove width ratio (W2/W1) of a maximum groove width W2 of the widened portion to a groove width W1 of the narrow groove portion is in a range 1.5≤(W2/W1)≤4.0, and a cross-sectional area ratio (A2/A1) of a groove bottom-side cross-sectional area A2 to a groove opening-side cross-sectional area A1 in a meridian cross-section is within a range 1.2<(A2/A1)<4.0 when the circumferential narrow main groove is divided into two parts at 50% of a maximum groove depth of the circumferential narrow main groove. The cross-sectional area ratio changes along the circumferential direction.

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 N−1, is strictly less than the angle A1.sub.j+1 relative to the layer C1.sub.j+1.

A tyre includes a tread portion including a tyre equator, a tread edge, a tread width which is a distance in a tyre axial direction from the tyre equator to the tread edge, a shoulder land portion including the tread edge. The shoulder land portion is provided with a plurality of first shoulder lateral grooves. Each first shoulder lateral groove includes an inner groove portion extending inwardly in the tyre axial direction of the tread edge and an outer groove portion extending outwardly in the tyre axial direction of the tread edge. Each first shoulder lateral groove, in a tread development view, has a groove area Sb of the outer groove portion extending in a region from the tread edge to an 125% position of the tread width is greater than a groove area Sa of the inner groove portion.

A tire 1 comprises a tread portion 2 comprising shoulder blocks 3 and crown blocks 4. The shoulder blocks 3 each has a ground contacting surface (3t) comprising an axially outer portion 6 extending axially inwardly from one of tread edges (Te) and a steeply oblique portion 7 extending axially inwardly from the axially outer portion 6 with a larger inclination angle with respect to the tire axial direction than the axially outer portion 6. The crown blocks 4 each has a ground contacting surface (4t) comprising a first oblique portion 10 inclined oppositely to the steeply oblique portion 7 and a second oblique portion 11 extending from and obliquely and oppositely to the first oblique portion 10. In a development view of the tread portion 2, longitudinal directions of the steeply oblique portion 7 and the first oblique portion 10 intersect at an angle from 70 to 110 degrees.

A pneumatic tire includes a tread; sidewalls; beads inward of the sidewalls; lug grooves formed in the tread and inclined symmetrically about the equator, an inclination angle α of the lug grooves with respect to the lateral direction being 15°≤α≤45°; and shoulder grooves connecting the lug grooves and inclined in an opposite direction to the lug grooves, a center line of the shoulder grooves at both sides meeting with two of the lug grooves at intersection points. A difference between distances L1, L2 from the equator to the intersection points and a tread width TW satisfy TW×0.03≤|L1−L2|≤TW×0.2. An average value of the distances and the tread width TW satisfy TW×0.15≤(L1+L2)/2≤TW×0.35. A groove area ratio of the tread is from 0.4 to 0.7.

A pneumatic tire has a plurality of main grooves extending in a tire circumferential directions and a plurality of land lines defined by the plurality of main grooves, on a tread face. At least one of the plurality of land lines protrudes outward in a tire diametrical direction from a profile line. A void ratio of a first area positioned on one side of a center of a width of the at least one land line is larger than a void ratio of a second area positioned on the other side. A protruding height of the second area from the profile line is larger than a protruding height of the first area.

A tire includes a plurality of main grooves extending in a tire circumferential direction and four or more rows of land portions defined by the main grooves. Moreover, a middle land portion and a center land portion have a plurality of through lug grooves that pass through the land portions in a tire width direction, respectively. Pitch lengths of the through lug grooves are in a range of from 7% or greater to 14% or less of a tire maximum ground contact length. Additionally, maximum groove depths of the through lug grooves are in a range of from 5% or greater to 65% or less of maximum groove depths of the main grooves.

A tire includes a circumferential direction groove and plural protrusions. The circumferential direction groove is formed in a tread face so as to open toward an outer side in a tire radial direction. The plural protrusions are formed so as to project to a projection height of from 0.1 mm to 1.0 mm from a groove bottom face or a groove side face of the circumferential direction groove, and are spaced apart by a spacing of from 0.1 mm to 1.0 mm. A center line MA, MB linking a center point of a leading end side with a center point of a base end side of each of the plural protrusions leans with respect to a perpendicular line HA, HB such that the leading end side of the protrusion is positioned further toward a tire rotation direction downstream side than the base end side of the protrusion when viewed along a tire width direction or the tire radial direction

By forming a ground contact edge side of lug grooves such that the groove depth becomes shallower in groove depth from the tire equatorial plane side toward the ground contact edge, and by setting an average angle of inclination formed between a tread face and a groove bottom to be not more than 5°, water expulsion is performed smoothly in the vicinity of the ground contact edge while securing the rigidity of land portions in the vicinity of the ground contact edge. This enables a high degree of both wet performance and dry performance to be achieved.

A pneumatic tire includes a tread; sidewalls; and beads. Lug grooves are formed in the tread inclining symmetrically about an equator, an inclination angle α of the lug grooves relative to the lateral direction being 15°≤α≤45°. A width W1 of the lug grooves at the tread edge and an interval W2 between the lug grooves at the tread edge satisfying 0.7≤W1/W2≤1.5. Shoulder grooves connecting lug grooves are inclined in an opposite direction to the lug grooves have an inclination angle β relative to the lug grooves being 80°≤β≤100°, a center position of the shoulder grooves being 15% to 35% of tread width TW from the equator. An area A1 of the shoulder grooves and an area A2 of shoulder blocks satisfy 0.2≤A1/A2≤0.6. A groove area ratio of the tread is 0.4 to 0.7.