Velocity-size relation (VSR): disk scale length r_d as a function of maximum rotation velocity V_max. We show a comparison between our ⟨ z ⟩ ≈ 0.5 data (circles) and the local VSR as found with data from Haynes et al. (1999b; the black dashed line indicates the fit to the local data (not shown in this figure) and the dotted lines depict the 3σ scatter). The blue solid line shows the fit to the distant sample, which is offset to smaller disk sizes by ⟨ Δlog r_d ⟩ = −0.10 ± 0.05 dex.