Plasticizing system which can be used in particular for the plasticizing of a tire diene elastomer composition containing, in combination: a plasticizing hydrocarbon resin, the glass transition temperature of which is greater than 0° C.; and a tri- or pyromellitate ester corresponding to the formula (I): in which the R radicals, which are identical or different, represent a hydrocarbon radical and the R′ radical represents hydrogen or COOR group. Also, a rubber composition incorporating the plasticizing system and the use of such a composition for the manufacture of a tire or tire semi-finished product made of rubber, in particular of a tire tread, exhibiting an improved wear resistance without having a detrimental affect on its wet grip.