A plasticizing system particularly useful for plasticizing a dienic elastomeric composition for tires, comprising a combination of: a plasticizing hydrocarbonated resin which has a vitreous transition temperature higher than 0 °C; and an tri- or polymellitate ester having the formula (I), in which the R radicals, whether identical or different, are a hydrocarbonated radical; R' is hydrogen or the COOR group. The invention also relates to a rubber composition comprising said plasticizing system and to the use of such a composition for the manufacture of a tire or a semi-finished rubber product for tires, particularly a tire tread having an enhanced wear resistance without compromising its adhesion to wet surfaces.