FWIW, my main ride is a 753r frameset in 57cm, 27.2mm post. I weigh around 195-lbs. (though I was closer to 220-lbs. as recently as a year ago) and I don't find my frame to be too flexy. I've ridden 531, 501, Tange Prestige, Tange Champion, Columbus SL, bonded aluminum (Vitus), oversized aluminum (Cannondale), titanium, gaspipe, Ishiwata 022, etc. In my experience, it may be slightly more flexy than a 531 or SL frameset, but it's not that noticeable, and nowhere near as flexy as a Vitus or my Speedwell Titanium.