The present technology provides a heavy duty pneumatic tire with a tread portion having a tread pattern including: a pair of circumferential primary grooves defined in a wave-like shape and extending in the tire circumferential direction; center lug grooves; center blocks; and circumferential secondary grooves extending in regions of the center blocks and open to the center lug grooves. The center lug grooves have two groove turning portions turned in a bend shape or a curved shape. The circumferential secondary grooves extend in an inclined manner relative to the tire circumferential direction. An inclination angle (.sub.4) of the circumferential secondary grooves relative to the tire circumferential direction is different from an inclination angle (.sub.1) of portions of the circumferential primary grooves relative to the tire circumferential direction, the portions extending toward the same side as a side in the tire width direction, toward which the circumferential secondary grooves are inclined.

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.

Taking a groove side-wall to a position at a groove depth from a tread face of lug groove as a tread-in side first inclined portion, and taking a groove side-wall from the position at groove depth to a groove bottom as a tread-in side second inclined portion, then the following A1 is set less than the following B1. When viewed in cross-section orthogonal to a length direction of the lug groove: A1 is an area of a region enclosed by an imaginary line passing through an end portion on a tread face side of the tread-in side first inclined portion and perpendicular to the tread face, by an imaginary line passing through an end portion on a groove bottom side of the tread-in side first inclined portion and orthogonal to the imaginary line, and by the tread-in side first inclined portion; and B1 is an area of a region enclosed by an imaginary line passing through an end portion on a tread face side of the tread-in side second inclined portion and perpendicular to the tread face, by an imaginary line passing through the deepest portion of the lug groove and parallel to the tread face, and by the tread-in side second inclined portion.

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 non-pneumatic tire for a wheeled tower of an in-field irrigation system has a circular array of hollow cavities within the tire body. In cross-sectional planes lying normally of the rotational axis, each cavity has a circumferentially elongated cross-section of greater circumferential length than radial width. Bulbous and concavely rounded terminuses of each cavity impart a dumbbell shaped cavity profile that omits stress failure points. The cavity width tapers in an axially inward direction toward a midplane of the tire, where the cavity width is narrowest. In use, collapse of the cavity at its narrow midpoint squeezes accumulate mud out from the cavities in self-cleaning fashion. The outer circumference of the tire features sloped areas whose axial measure decreases toward the midplane. In use of the tire, the sloped areas draw mud inwardly toward the midplane and self-fill the ground beneath the tire, and thereby lessening overall rut formation.

A pneumatic tire, including: a lug groove opening at an end of a ground contact surface of a tread portion and extending toward the tire equatorial plane of the ground contact surface to terminate before reaching the tire equatorial plane; a communication groove making a corresponding pair of the lug grooves located on respective sides of the tire equatorial plane communicate with each other; and at least one widthwise groove, formed in a ground contact surface region demarcated between the end of the ground contact surface and the tire equatorial plane and between one pair and another pair adjacent thereto in the tread circumferential direction of the lug grooves and the communication groove communicating therewith, such that the widthwise groove extends in a direction of a tread width and an end thereof on the outer side in the tread width direction terminates within the ground contact surface region.

A heavy-duty tire is described herein. The heavy duty tire includes a carcass, a tread located radially outward of the carcass, and a tread having a plurality of lugs. The lugs extend radially outward from an inner tread and are located between the first and second lateral tread edges. The tread further includes a first row of lugs extending from the tread lateral edge axially inwards toward the centerplane, and a second row of lugs extending from the opposite tread lateral edge and axially inwards toward the centerplane. The lugs of the first and second rows are separated by a plurality of shoulder grooves, wherein the first row of lugs are aligned with the second row of lugs, a center row of lugs located between a first and second offset lug, wherein all of the lugs in each row are aligned circumferentially.

A tire includes a tread provided with blocks formed among substantially longitudinal and transverse grooves, wherein among the blocks particularly broad intersections are formed, for example, by staggering substantially transverse grooves of circumferential rows axially in side-by-side relationship, of blocks with rounded corners, and wherein, inside such broad intersections, a stocky-shaped protrusion is arranged which has a lateral stiffness greater than the lateral stiffness of the surrounding blocks.

A pneumatic tire includes inner land portions, formed between a center main groove and outer main grooves on both sides of the center main groove, which are divided into blocks by sub-grooves. A pair of the sub-grooves positioned on both sides of the center main groove is inclined in the same direction with respect to the tire width direction, disposed such that openings on the center main groove side overlap in the tire circumferential direction, and the circumferential components of the sub-grooves are continuous throughout the tire circumference. A groove width of the sub-grooves changes at a middle portion in the length direction such that the sub-grooves include a narrow width section positioned on the outer main groove side and have a groove width W1 that is relatively small, and a wide section positioned on the center main groove side and having a groove width W2 that is relatively large.

A non directional pneumatic tire is provided for an agricultural irrigation system. The tire includes first and second side walls and a radially outer wall defining an internal inflation chamber. A non directional tread pattern is defined on the tire and includes a plurality of longitudinal protrusions positioned substantially parallel to a rotational axis of the tire. The longitudinal protrusions are arranged in first and second rows extending from the first and second side walls toward and across the equatorial plane of the tire. The longitudinal protrusions of the first and second rows circumferentially alternate with each other and there is a circumferential spacing between adjacent longitudinal protrusions at the equatorial plane so that no portion of one longitudinal protrusion circumferentially coincides with or overlaps another.