Dear Boys and Girls, I am not trying to muddy the waters but just lend some of what has helped me. I started using the reach measurement a year, ago, and it has MOSTLY been helpful when working from a bike that I know fits me very well and trying to find something else that will fall in that ballpark. I can measure a bike and know, definitively, when the reach will be outside of my range. Having said that, I have found that Front Center (from front axle to center of cranks) and Rear Center (chainstay) are easier measurements to take and almost just as pertinent as reach, although comparisons can only be done when frame angles are similar. The bottom line for me is that of the bikes I have gone through I keep a database of frame measurements (with Reach, Front Center, and Rear Center, along with a couple others), and classic top-tube or seat-tube measurements are meaningless.