The invention relates to improving the endurance of the beads of a radial tire for a heavy vehicle of construction plant type by reducing the cracking that starts on the axially outer face of the turn-up and spreads through the polymer coating and filler materials. According to the invention, a transition element made of a polymer transition material, is in contact, via its axially inner face, with the polymer coating material of the axially outer face of the turn-up and, via its axially outer face, with the polymer filler material, and the elastic modulus at 10% elongation of the polymer transition material is somewhere between the respective elastic moduluses at 10% elongation of the polymer coating material and of the polymer filler material.

The invention provides a method for producing a modified conjugated diene (co)polymer, the method including comprising: a modification reaction step including causing an organic silane compound to react with a conjugated diene (co)polymer having an active site at the active site, the organic silane compound having a characteristic group for forming a silanol group through hydrolysis and, in the vicinity of the characteristic group, (i) a functional group which binds the organic silane compound to the conjugated diene (co)polymer via addition to or substitution at the active site and which promotes reaction between the silanol group and a reinforcing filler after the addition or substitution reaction, or (ii) a functional group which promotes reaction between the silanol group and a reinforcing filler, and a hydrolyzation step performed after the modification reaction step; a modified conjugated diene (co)polymer having, at a molecular end of the conjugated diene (co)polymer, a silanol group, and a functional group in the vicinity of the silanol group, the functional group accelerating reaction between the silanol group and the reinforcing filler; a rubber composition containing the (co)polymer and carbon black having specific characteristics; and a tire formed from the rubber composition.

[Object] A tire 2 that has quietness and durability improved without reducing steering stability, is provided.

[Solution] The tire 2 includes: a pair of beads 12; a carcass 14 that is extended on and between the beads 12 on both sides; and a pair of strips 24 that extend almost outward from the beads 12 along the carcass 14 in the radial direction. The beads 12 include cores 34, first apexes 36, and second apexes 38. The carcass 14 includes a carcass ply 44, and the carcass ply 44 includes a main portion 46 and turned-up portions 48. The turned-up portions 48 are disposed between the first apexes 36 and the second apexes 38. The turned-up portions 48 contact with the main portion 46 in portions radially outward of outer ends 42 of the first apexes 36. A position of an outer end 64 of each strip 24 is equal, in the radial direction, to a position Pb at which the maximum width is obtained, or the outer end 64 of each strip 24 is disposed radially inward of the position Pb at which the maximum width is obtained.

The present invention provides a pneumatic tire having excellent durability. Provided is a pneumatic tire including a sidewall and a carcass, the sidewall being produced from a rubber composition for a sidewall which has a specific sulfur content, the carcass being produced from a carcass cord covered with a rubber composition for a carcass topping, and the sulfur contents of the rubber composition for a sidewall and the rubber composition for a carcass topping satisfying a specific relationship. Provided is a pneumatic tire including a clinch and a carcass, the clinch being produced from a rubber composition for a clinch which has a specific sulfur content, the carcass being produced from a carcass cord covered with a rubber composition for a carcass topping, and the sulfur contents of the rubber composition for a clinch and the rubber composition for a carcass topping satisfying a specific relationship.