The present invention provides a pneumatic tire and a rubber composition for tires, which have improved durability at high temperatures and during high-speed running while ensuring good ice performance. The present invention relates to a pneumatic tire, including a tread, the tread including blocks having an average ripe density of 1.0 cm/cm.sup.2 or higher and an average height of 0.6 to 2.0 cm, the blocks containing a rubber composition having a tan δ at 100° C. of 0.179 or less as determined at an initial strain of 10%, a dynamic strain of 2%, and a frequency of 10 Hz, and has a ratio of the modulus at 100° C. to the modulus at room temperature of 69% or greater as determined in accordance with JIS K6251:2010.

A first land region is defined between a first main groove and a second main groove extending in a tyre circumferential direction. The first land region is provided with a first oblique groove and a second oblique groove. The first oblique groove extends obliquely with respect to a tyre axial direction from the first main groove to have an end portion terminating within the first land region. The second oblique groove extends obliquely with respect to the tyre axial direction from the second main groove to intersect with a middle groove portion of the first oblique groove and terminate there.

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 pneumatic tire includes a plurality of circumferential main grooves, a plurality of lug grooves, and a plurality of blocks. Raised bottom portions are formed on groove bottoms of shoulder circumferential main grooves that are the circumferential main grooves, among the plurality of circumferential main grooves, positioned most outward in a tire lateral direction, and shoulder lug grooves that are the lug grooves, among the plurality of lug grooves, positioned outward from the shoulder circumferential main grooves in the tire lateral direction and connected to the shoulder circumferential main grooves from outer sides in the tire lateral direction. The raised bottom portions are formed so as to exclude at least intersection portions where the shoulder circumferential main grooves and the shoulder lug grooves intersect.

A tyre has a tread portion. The tread portion includes a land region defined between a first edge extending in a tyre circumferential direction and a second edge extending in the tyre circumferential direction. The land region is provided with a first lateral groove extending from the first edge toward the second edge and terminating within the land region, a vertical groove connected with the first lateral groove, extending in the tyre circumferential direction, and having both end portions terminating within the land region, and a sipe connected with the vertical groove and extending therefrom toward the second edge.

A pneumatic radial tyre includes a plurality of shoulder lateral grooves crossing shoulder lard regions. In a cross-sectional view of at least one of the shoulder lateral grooves taken along a groove width center line thereof, a groove bottom of the shoulder lateral groove includes a first bottom surface portion arranged on an inner side in a tyre axial direction and a second bottom surface portion extending between the first bottom surface portion and the tread surface outer end in a concave arc shape having a radius of curvature.

A tire includes a block 30. The block 30 includes a land 36b, a transverse groove 48b, a longitudinal groove 50b, and a side surface 38b. The land 36b is flat. The transverse groove 48b is recessed from the land 36b. The transverse groove 48b has inner and outer ends 52 and 54 in an axial direction of the tire. The inner end 52 of the transverse groove 48b is open on the side surface 38b. The outer end 54 of the transverse groove 48b is not open on the side surface 38b. The transverse groove 48b is localized in the inner region of the block 30 in the axial direction.

A pneumatic tire comprises a tread portion which has, on each side of the tire equator, a first tread edge, a second tread edge and a third tread edge which are occurred under tire loads of 100%, 75% and 50% of a regular tire load, respectively. Between the third tread edge and the tire equator, a circumferentially continuously extending main groove is disposed. A shoulder region between the main groove and the first tread edge is provided with a first inclined groove which extends so as to intersect with the first tread edge, the second tread edge and the third tread edge. The depth of the first inclined groove at the first tread edge is smaller than the depth at the second tread edge and the depth at the third tread edge.

A heavy duty pneumatic tire includes a tread pattern that includes circumferential main grooves, a center wide groove extending in a center region between the circumferential main grooves, and center lug grooves disposed in a first center region and a second center region on either side of the center wide groove in the tire lateral direction, the center lug grooves having a linear shape and opening to the center wide groove. The center lug grooves and the circumferential main grooves have a narrower groove width than shoulder lug grooves disposed in a shoulder region. The center lug grooves of the first center region and the center lug grooves of the second center region extend parallel with one another. The center wide groove has a constant groove depth that is shallower than the maximum groove depth of the circumferential main grooves and the center lug grooves.

A pneumatic tire includes at least four circumferential main grooves extending in a tire circumferential direction and at least five land portions defined by the at least four circumferential main grooves. A center land portion includes a plurality of center lug grooves extending through the center land portion in a tire lateral direction and disposed at predetermined intervals in the tire circumferential direction, and a plurality of center blocks that are defined by the plurality of center lug grooves. The center blocks each include a narrow shallow groove that extends through the center block in the tire lateral direction and that remains open when the tire comes into contact with the ground.