Using fixed- t dispersion relations together with experimental data on π − p → π 0 n we determine the real and imaginary parts of the s -channel helicity amplitudes (SHA) of the vector (ϱ) exchange contribution to πN → πN . The results are in good agreement with amplitude analyses. We also make comparison with finite-energy sum-rules (FESR) and discuss certain implications. Furthermore, on the basis of two-component duality and FESR we calculate the tensor ( f ) contribution. The t -structure of the resulting SHA is compared with independent information on hadronic tensor exchanges.