This paper demonstrates that the addition even of small amounts of vinylsilane strongly enhances the reinforcement of silica-filled rubber compounds. With regard to coupling efficiency, processibility, and health concerns the vinyltriethoxysilane VP Si 225 as well as the oligomerized vinylsilane Dynasylan 6498 are best suited for the rubber industry. Furthermore, the influence of the amount of VP Si 225 and the amount of peroxide initiator as well as the influence of the silica surface area and the silica loading on selected in-rubber data are presented.