Originally Posted by Ranger
Well they recommend an overall reach of 69.725 cm. The 62cm Specialized Allez Sport with the 90 mm stem has an overall reach of 69.5 cm. So in other words, they were WRONG. Taking the wrenchscience measurements into account, the 62 would be the perfect fit for me. Problem was that it felt horrible to ride. I was REALLY having to reach.
The reach of the handlebars matter too (not just stem). That's what can throw the measurements off.
The saddle fore/aft and seat tube angle affect the top tube length too. A 58cm top tube with a 73.5 STA is going to feel 1.0 cm longer (at least) than a bike with a 58cm top tube and 72.5 STA.