Originally Posted by
rodar y rodar
It`s a pretty murky subject for me, too. Feel free to shoot me down, but I think an awful lot of it is guesses until the specific combination you`re considering has actually been built and tested. Aside from manufacturers` websites and catalogues, here`s a big collection of geometry data:
http://hiddenfortress.org/geometry/index.html
I'm not so sure everything is unknown and it all needs to be tested empirically. There are some configurations that have been in use for quite a while, such as the 73/73 degree angles combined with a 7 to 7.5cm drop and 42 to 44 cm chainstays. Racing, sport-tour, and distance bikes have all used something quite like this, dating at least back the the PX-10s of the mid and late '60s, into the Trek steel bikes of the late '70 through the mid-'80s. Today I see it on the Toei randonneur reviewed in BQ perhaps 18 months ago, and the current Boxdog Pelican.
Some good configurations are known and have been proven in the marketplace, as well as on the open road.