The use of sulfur-functional organosilanes like bis(triethoxysilylpopyl)tetrasulfide (Si 69) as coupling agent in silica-filled rubber compounds is well-known. A main application of this kind of silane is the use in sulfur-vulcanized diene rubbers. Apart from diene rubbers the MRG industry uses a variety of special elastomers. There, depending on the kind of elastomer, other vulcanization systems with peroxides or metal oxides as curing agents are required. This paper demonstrates the potential of special silanes for special purpose elastomers. Apart from sulfur-functional derivatives, silanes with double bonds or with hetero-functional groups are presented. Application examples are given and the influence of the amount of silane on the in-rubber properties is demonstrated. Proposed reaction mechanisms are discussed.