A point many lose, is that Colnagos are frames made with italian racing geometry.
That means low bottom brackets, slanted head tubes and shorter top tubes.
They are thought to be setup, on "long and low" stems, so your weight would be properly balanced.
I have had Colnagos ( C40s, C50s, EP, EC ) on sizes 54,55,56, 56 "freuler", 52s, 57 and 58
I can sure get the exact same fit on all those by using the right combination of stem and seatpost seatback.
But the one that really fits, handles, climbs, descends and rolls perfectly for me is the 56 traditional on a 120mm stem, (-6° no spacers, or the equivalent fit on -17° ). It simply puts me on the right place. no doubt about it. Coincidentally this fit is "balanced" so I have exactly 56cm "Saddle-tip-to-center-bars" and 56cm "center-bars-to-center-front-hub".
Some people don't know that and tend to set up their Colnagos on "short and high" stems and that is IMHO wrong. even more with compact bars with the shifters pointing up. While that setup can be right on an american geometry sloping frame, they are not good for the italian traditional geometry.
there is an interesting read on RKP about this herehttp://redkiteprayer.com/2009/10/a-study-in-geometry/
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Can we put this myth to bed? Italian stage-race geo is described in detail in the CONI manual, and that geometry is largely unchanged on today's Italian bikes. The long and low thing is bollocks. For example, a 56 cm Colnago should run a 9.5-10 cm stem based
on frame proportionality (body morphology can dictate otherwise, of course). You can also see how this works just by looking at a bike: look at where the end of the bar (curve) ends up in relation to the front hub -- with a proportional stem, it will sit right over the hub.
Super high bars with shifters pointing way up usually just indicates a missized frame --- likely due to an error in seat height. And, generally, regarding shifter position, compact bars are a different world than trad. bars.