We measured the bar pattern speed of a sample of 6 SB0 galaxies using the Tremaine-Weinberg method. We derived the ratio, {cal R}, of the corotation radius to the length of the bar semi-major axis. For all the galaxies, {cal R} is consistent with being in the range from 1.0 and 1.4, i.e. that they host fast bars. This represents the largest sample of galaxies for which {cal R} has been measured this way. We compared this result with recent high-resolution N-body simulations of bars in cosmologically-motivated dark matter halos, and conclude that these bars are not located inside centrally concentrated dark matter halos.