I'm with Garth, although he stated it better than I did. Even the Guimard method, which was adopted by LeMond bikes, with its slack seat angle and relatively long top tube worked great when we sized it by fitting the customer to a bike with proper top tube length for him/her. The seat tube length / standover always worked out well if the top tube length was correct for the rider. Minor adjustments would dial in the final fit with the first few rides, but we rarely needed to change stem length; stem height perhaps, and seat post verticle. But rider setback always seemed pretty close first off - of course we would recommend a frame with geometry that best suited the rider to begin with. But sizing that frame always worked best based upon tt length.
Greg Overton Denver vicinity, Colorado
Quoting Bianca Pratorius <biankita@comcast.net>:
> To me standover height is not relevant because if you buy your frames
> on the basis of top tube c-c length it automatically takes into
> consideration various tube diameters. If a tube is 1 inch diameter or 3
> inch diameter (extreme hypothetical) the position of the seat post and
> stem quill will still be exactly the same for given frame angles. It
> doesn't matter how the quoted seat tube measurement is given c-t, c-c,
> center to virtual top or center to virtual center, as long as the
> person measuring the seat tube tells you how he arrived at the
> measurement. Some 54 c-c top tubes come with 54 c-c seat tubes - some
> with 54.5 seat tubes and some with 55, but I never had a top tube c-c
> real or virtual measurement throw me for a loop. If I know that one
> measurement the bike will fit assuming it is a road bike and not a
> mountain bike or a city bike. A bike should be sized for your spine
> unless you have very short or long legs (relative) in which case you
> should probably be getting a custom bike. Standover height shouldn't
> even enter into the equation because one can always stand over the bike
> with it held slightly at an angle if it has a particular high bottom
> bracket. Buying a bike for standover height is kind of like setting
> saddle height based on whether or not your feet can still touch the
> ground while sitting on the saddle.
>
> Garth Libre in Miami Fl. USA _______________________________________________