Curable composition for hard rubber and the use thereof

A radial tire comprising a carcass ply composed of cords arranged in the radial direction of tire, the both end portions of the carcass ply being turned up at a bead to fasten, and a bead filler being positioned between the carcass ply and the turned-up end portion thereof and extending from a location just above a bead wire toward the side wall of the tire, said radial tire being improved in that said bead filler is made of a cured composition comprising (1) at least one rubber selected from the group consisting of natural rubber, a diene rubber and a diene copolymer rubber, (2) a sulfide resin as a curing agent having the following general formula:

• ##STR8## wherein X is methylene group, ethylene group, --S-- or --S--S--, R.sup.1 and R.sup.2 are independently a C.sub.1-10 alkyl or alkylene group, Y.sup.1 and Y.sup.2 are independently the residue of a phenol compound, p is an integer of 2 to 8, and n is an integer of 2 to 5, (3) a phenolic thermosetting resin and (4) a hardener for hardening said thermosetting resin.