Rubber composition for tire comprising an organosilicon coupling system

A tire comprising a composition, based on at least one isoprene elastomer, an inorganic filler as reinforcing filler and an (inorganic filler/isoprene elastomer) coupling system which provides the bonding between the inorganic filler and the isoprene elastomer, wherein said coupling system comprises:

• as first coupling agent, a silane polysulfide compound (hereinafter “Compound I”) that corresponds to the formula (I):
• Y1—Z1—SX—Z2—Y2 (I)
• wherein:
• x is an integer from 2 to 8;
• Z1 and Z2, which are identical or different, each represent a divalent hydrocarbon radical comprising from 1 to 18 carbon atoms;
• Y1 and Y2 which are identical or different, each correspond to one of the following formulae:
• wherein:
• the R1 radicals, which are unsubstituted or substituted and identical to or different from one other represent a C1-C18 or C6-C18 aryl group;
• the R2 radicals, which are unsubstituted or substituted and identical to or different from one another, represent a C1-C18 alkoxyl or C5-C18 cycloalkoxyl group;
• as second coupling agent, an at least bifunctional organosilicon compound (hereinafter “Compound II”) which can be grafted, on the one hand, to the inorganic filler by means of a silyl functional group G and, on the other hand, to the elastomer by means of an azodicarbonyl functional group, the organosilicon compound having the formula:
• A-CO—N=N—CO—Z—G (II)
• wherein:
• G is the silyl functional group bearing a hydroxyl or hydrolysable group attached to a silicon atom of the compound;
• Z is a divalent bonding group connecting the azodicarbonyl functional group to the silyl functional group;
• A represents a monovalent hydrocarbon group or the group of formula Z′-G′ wherein:
• Z′, which is identical to or different from Z, is a divalent bonding group which makes it possible to connect the azodicarbonyl functional group to another silyl functional group G′;
• G′, which is identical to or different from G, is a silyl functional group bearing another hydroxyl or hydrolysable group attached to a silicon atom;
• A, Z and if applicable Z′, independently, may comprise a heteroatom.