Large tires, the tread of which has a mean volumetric void ratio over the entire tread of greater than 10%, comprise a composition based on at least one diene elastomer, on a vulcanization system and from 0.10 to 1 phr of at least one organic polysulfide.

An outer surface TS of a tire 2 includes a tread surface T and a pair of side surfaces S. A plurality of arcs representing a contour of the tread surface T include a pair of crown arcs. A ratio of a radius CR1 of a first crown arc to a radius CR2 of a second crown arc is not less than 1.10 and not greater than 1.70. A total groove volume of a first circumferential groove 48 located in a zone from an equator to a first tread reference end TE1 is larger than a total groove volume of a second circumferential groove 50 located in a zone from the equator to a second tread reference end TE2.

A pneumatic tire includes two circumferential main grooves disposed in the region on one side of a tire equatorial plane as a boundary and a land portion defined by the two circumferential main grooves. The land portion includes a circumferential narrow groove extending in the tire circumferential direction and sets of a first and a second lug groove extending in the tire lateral direction through the circumferential narrow groove. The first lug groove includes an end portion that opens to the edge portion on one side of the land portion and another end portion that terminates within the land portion. The second lug groove includes an end portion that opens to the edge portion on the other side of the land portion and an end portion that terminates within the land portion. The first lug groove and the second lug groove are alternately disposed in the tire circumferential direction.

A tire comprises a directional tread of width (W), having a total volume VT, comprising voids (221, 211, 212) defining a voids volume VE. There is defined a volumetric voids ratio TEV=VE/VT, part of the voids (211) delimits blocks (21A, 21B) which are organized into patterns (26) of blocks of pitch P succeeding one another in the circumferential direction (X). Part of the voids forms sipes (211, 212) in one of the patterns. The sipes density SD corresponds to the ratio of a sum of the projected lengths (lpyi) of the sipes in an axial direction to the product of the pitch P of the pattern times the width (W), all multiplied by 1000. SD in any pattern of pitch P is comprised between 10 mm.sup.−1 and 70 mm.sup.−1. TEV is at least equal to 0.29 and at most equal to 0.35.

A tire comprises a directional tread which forms a contact patch AC during running. The tread comprises a plurality of blocks (21A, 21B) which form a contact surface SC. The surface voids ratio is defined by TES=(AC−SC)/AC. The blocks (21A, 21B) are organized into patterns (26) of blocks of pitch P which succeed one another in the circumferential direction (X), in a pattern comprising at least one sipe. The sipes density is defined by the formula

[00001]$\mathrm{SD}=\frac{{.Math.}_{i=1}^n\mathrm{lpyi}}{P*W}*1000,$

where n is the number of sipes, lpyi is the projected distance of the sipe i in the axial direction (Y), and W is the width of the tread. Simultaneously, SD is at least equal to 10 mm-1 and at most equal to 70 mm-1, and TES is at least equal to 0.40 and at most equal to 0.70.

A tire comprises a tread of width (W), having a total volume VT, comprising voids (221, 211, 212) defining a voids volume VE. There is defined TEV=VE/VT. Voids (211) delimit blocks (21A, 21B) organized into patterns (26) of pitch P succeeding one another in the circumferential direction (X). Part of the voids forms sipes (211, 212) in one of the patterns. SD corresponds to the ratio of a sum of the projected lengths (lpyi) of the sipes in an axial direction (Y) to the product P times W, multiplied by 1000. The tread forms a contact patch AC and blocks (21A, 21B) form a contact surface SC: TES=(AC−SC)/AC. For the tread when new, SD in any pattern of pitch P is comprised between 10 mm.sup.−1 and 70 mm.sup.−1, and TES/TEV is comprised between 1.5 and 1.9.

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.

A tire includes medial knobs and lateral knobs in right and left zones extending around the circumference. The tire includes a central zone in between two arrays of medial knobs. The central zone may include no knobs or knobs with a height less than 50% of the height of the lateral knobs.

To provide a narrow and large-diameter tire capable of improving noise performance at high speeds without compromising handling performance at low temperatures.

The tire has a tread portion formed of an elastomer composition. A relationship between a tire outer diameter (Dt) and a tire cross-sectional width (Wt) satisfy a following expression (1). The tread portion includes at least one circumferential groove extending in a tire circumferential direction. A rubber thickness at a groove bottom of the circumferential groove is 0.05 to 0.25 times a maximum thickness of the tread portion. The elastomer composition has a phase difference δ of 5.0×10.sup.−2π [rad] or less between a maximum value of strain and a maximum value of stress when repeatedly deformed at a temperature of 30 degrees Celsius and a frequency of 10 Hz in a dynamic viscoelasticity test;

1963.4≤(Dt.sup.2×π/4)/Wt≤2827.4  (1).

In a tire having a specified mounting direction, groove area ratios Rin and Rout in ground contact regions on the vehicle inner and outer sides, respectively, satisfy Rin>Rout, average land portion areas Ain and Aout of intermediate regions Min and Mout on the vehicle inner and outer sides, respectively satisfy Ain<Aout, the number of blocks Nin, Nout in the intermediate regions Min, Mout, respectively, satisfy Nin≥1.5×Nout, total sipe lengths Sin, Sout in the intermediate regions Min, Mout, respectively, satisfy Sin<Sout, and sipes formed in the intermediate region Mout have a three-dimensional structure in a range of 70% or more of a sipe length.