Abstract: A bead filler rubber composition, comprising:(A) a resin forced rubber composition comprising vulcanizable rubber including 5 to 100 parts by weight, based on 100 parts by weight of the rubber, of fine short fibers of thermoplastic polymer having ##STR1## groups buried therein, and the vulcanizable rubber and the thermoplastic polymer being grafted to each other through a phenol formaldehyde resin precondensate at an interface of the fiber;(B) a diene rubber; and(C) carbon black,wherein the following conditions (i) through (iv) are satisfied:(i) the amount of said thermoplastic polymer is 2 to 20 parts by weight based on 100 parts by weight of the total amount of the rubber constituents;(ii) the ratio of the rubber is such that the total amount of the natural rubber or polyisoprene in the component (A) and the component (B) is 100 to 55% by weight;(iii) the amount of the carbon black is 50 to 70 parts by weight on 100 parts by weight of the total amount of the rubber constituents; and(iv) the vulcanizate deri