Though I think that the overall gist of this thread is pretty silly, yes, on my bike with a 53/39 (and a 12-27 in back, fwiw), I can ride quite happily in the flats on my 39, unless the pace is, say, above 22 mph. Admittedly, I am more often in the big ring, but when you don't have a compact, the small chain ring is more than just for climbing.