Tire tread has a central rib (411-413) and two lateral ribs (421-422) which are separated by circumferential grooves (141-144). A first lateral rib (421) adjacent to the outer axial edge of the tread and a central rib have a first portion (4211, 4111, 4121, 4131) the axial width of which exceeds 20% of the axial width of the relevant rib made from a first rubber composition containing an elastomer and a reinforcing filler consisting predominantly of carbon black, and an axially adjacent second portion (4212, 4112, 4122, 4132) made of a second rubber composition containing an elastomer and a reinforcing filler a minority proportion of which consists of carbon black. The second rubber composition has a tan d0 value which is less than the tan d0 value of the first rubber composition, the tan d0 values being measured at a temperature of 0 C and under a stress of 0.7 MPa.

Tire comprising a directional tread that has two edges and a center. The tread comprises a plurality of blocks, each block extending continuously along an overall curvature C from one of the edges towards the center of the tread, forming a block central end provided with a central wall. Each block has a width WB and a length LB, this width increasing from the block central end in the direction of the edge. All or some of the blocks of the tread include a median sipe of length S and extending from the block central end along a curvature C substantially identical to the curvature C of the block.

A tire for running on rough terrain for which an intended tire rotational direction is specified, and which comprises a tread portion provided with crown blocks disposed on the tire equator. Each of the crown blocks comprises a V-shaped crown block main portion which bends convexly toward a circumferential direction opposite to the intended tire rotation direction, and only two crown fin portions projecting from the crown block main portion toward the above-said circumferential direction opposite to the intended tire rotation direction.

An agricultural tire according to an exemplary embodiment of the present invention is provided with plural lug blocks that are provided at a tread portion, and with protruding portions that protrude towards an outer side in a tire width direction from an end portion on the outer side in the tire width direction of the lug blocks, and that have a surface that, if an angle of a virtual straight line extending towards the outer side in the tire width direction is taken as 0, faces a tire rotation direction at an angle of not less than 35 and not more than 55.

A pneumatic tire for all-terrain vehicle is disclosed which comprise a tread, and a plurality of primary blocks extending in a tire circumferential direction disposed symmetrically on the tread with respect to a center line of the tread, each primary block being evenly spaced with each other; two pairs of secondary block arrays arranged respectively on areas between any two adjacent primary blocks which are symmetrical with respect to the circumferential center line of the tread; a prior ground engaging edge created on a ground engaging surface when the ground engaging surface of the primary blocks may be inclined to a moving direction of the tire; and a plurality of stepped humps located on the prior ground engaging edge. The turning manipulation performance of the tires in sandy land can be highly improved while the straight-running traction performance is not affected due to the above configuration of the invention.

A tire (10, 10) for rotation about an axis of rotation (12) has a first wall portion (14) having a partially conical form, and a second wall portion (16) integrally formed and interconnected with the first wall portion at a transition region (18) so as to define an annular recess. A closure-limiting configuration includes a number of tubular reinforcing elements (20) arrayed around the annular recess. Each tubular reinforcing element has a wall with a closed cross-section. The tubular reinforcing elements (20) are spaced around the annular recess such that deformation of a compressed region of the tire under a load causes a change in shape of the tubular reinforcing elements in the compressed region.

Tire and tread for a vehicle for agricultural use having reduced attack to leading faces of tread bars, at axially outer ends thereof, by stubble remaining after harvest, thereby reducing risk of chunking of axially outer ends of the bars. The tire and tread has a plurality of bars, a bar having, in any axial plane (P.sub.xy) parallel to the axis of rotation, a leading profile and a trailing profile. The angle (A) of the straight line (T) tangential to the leading profile at a point (M) on the leading profile, with respect to an equatorial plane (P), increases continuously, from an axially outermost point (E) of the leading profile, when the axial distance (L) between the point (M) and the point (E) increases, the angle (A) reaches a maximum value (A.sub.m) at a point of inflection (I) of the leading profile, and the radius of curvature (R) at any point (M), positioned axially between the axially outermost point (E) and the point of inflection (I), is at least equal to 0.4 times the height of the bar.

A pneumatic agricultural tire includes first and second rows of angled lugs. Each lug is provided with a leading wall rising up from a tread floor to a leading edge of the lug surface. The leading wall has a wedge shaped leading nose rising up from the tread floor and sloped in the trailing direction so that ground stubble is engaged by and pushed aside by the wedge shaped leading nose thereby reducing stubble damage at a root of the leading wall.

A tire with improved uneven wear resistance has a designated tire rotation direction and includes inclined grooves in both halves of the tread surface divided by the tire equatorial plane, the inclined grooves extending inward in the tire width direction from the tread surface edge side, being inclined opposite the tire rotation direction, and being aligned in the tire circumferential direction; and an inter-inclined-groove land portion formed between each pair of inclined grooves that are adjacent in the tire circumferential direction. Along a land portion edge of the inter-inclined-groove land portion on the tire rotation direction side thereof, a point P1 located of the tread half-width from the tire equatorial plane in the tire width direction is positioned on the tire rotation direction side of a point P2 located of the tread half-width from the tire equatorial plane in the tire width direction.

A pneumatic tire for heavy load including, on a tread surface thereof, land portions defined by a plurality of lug grooves each extending in the tread width direction while opening at one end thereof to the tread ground-contact end, in which: the tire has a negative ratio Nc of 2% to 10% in a tread center side region; the lug groove has a depth da, the land portion has a width Rw, and the land portion has an extending length L, so that the land portion center line has a length of 0.5 L or more in a segment where Rw/da is 1.3 to 2.5; and the land portion center line has a length of 0.3 L or more in a segment having a tilt angle of 60 or less relative to the tire equator direction.