The effect on the peeling energy, G, of glass/styrene-butadiene rubber (SBR) assemblies of the length, N, of the alkyl chain, ranging from 4 to 30 carbon atoms, of silane coupling agents is determined. Experimentally, it is shown that G strongly increases with N. Therefore, considering that the theological model of adhesion (or model of multiplying factors) is valid, G is assumed equal to the product of three terms: the reversible adhesion energy, W, at the interface, the viscoelastic dissipation factor, Phi, of SBR and a ＇＇molecular factor＇＇ to be determined. Finally, it appears that this latter factor depends linearly on N. Such a result should be consistent with an extraction (＇＇suction＇＇) process of the silane alkyl links from bulk SBR during peeling experiments.