This invention relates to use of stabilized unsymmetrical coupling agents for use in conjugated diene-based rubber compositions reinforced with silica-based reinforcement, namely use of stabilized 2-benzothiazyl-3-(triethoxysilylpropyl) disulfide and 3-(triethoxysilyl)propyl-N-maleamic acid. Said stabilized unsymmetrical coupling agent materials may be provided for mixing with said diene-based rubber(s), for example, as individual materials, as at least one of said materials being pre-reacted with aggregates of precipitated silica, said precipitated silica having hydroxyl groups (e.g. silanol groups) on its surface. The invention includes an article of manufacture, including a tire, having at least one component comprised of such rubber composition.