Comparison of the predictions of the model with r_λ − c = −0.4 and s = 0.4 (red lines) against the observations from the SPARC catalogue (grey circles). We adopt two different velocity definitions for the TF relation: V_2.2, the circular velocity at 2.2R_d, and V_flat, which we compare with V_c(5R_d) where our model rotation curves are approximately flat. The light red band shows the 1σ intrinsic scatter of the model.