The invention concerns a rubber tyre composition made from at least one diene elastomer, an inorganic filler as a reinforcing filler, a coupling agent linking the inorganic filler and the diene elastomer, characterised in that the coupling agent is an azo-silane compound of the following formula (I): (G
1 )
3-a (G
2 )
a Si-Z-NH-C(O)-N=N-G4 (I) in which: - G
1 , identical or different, each represent a monovalent hydrocarbon group chosen from the linear or branched, substituted or unsubstituted alkyls having 1 to 18 carbon atoms, the substituted or unsubstituted cycloalkyls or aryls having from 5 to 18 carbon atoms, - G
2 , identical or different, each represent a hydroxyl group or a monovalent group in the form (G
3 )
n -OG
1 , in which G
3 is a divalent linking group comprising 1 to 18 carbon atoms and containing one or more heteroatoms chosen from O, S, Si and N, and n is a number greater than or equal to 0 and less than or equal to 18, - G
4 represents an aromatic or heteroaromatic, substituted or unsubstituted group, or a substituted or unsubstituted alkyl group, - Z represents a divalent linking group comprising 1 to 18 carbon atoms, - a is equal to 1, 2 or 3.