Originally Posted by Campag4life

Thanks for your comments jmX. Could you put a tape on your saddle height for me? What is the dimension from your BB center to the top of the saddle along the seat tube?

Could you post a quick pic of your size 58 Roubaix? Curious to see how it looks compared to my 58 Roubaix...see below...since we are identical in size.

I love the Roubaix however believe the 58 is a bit big for us but really depends what riding position one prefers. All said, fit on a roadbike isn't an absolute, but rather a choice. I have in fact considered owning two road bikes whereby I set one up a bit less aggressive than the other. Like yourself, no doubt you can ride in a lot of different positions and so can I. My neck starts to complain if the bike gets too aggressive on longer rides however and why I prefer the longer head tube of the Roubaix. The sizing chart shows the cut off point between 56 and 58 for the Roubaix at 6'0". So obviously we could ride either and you do. I am of the mind that arms closer in but more angled down may even be more comfortable than more stretched out and higher hand position of the 58....effectively the same reach dimension from saddle tip to handlebar center...same distance angled down to a lower handlebar (dimension X below)...if that makes sense. I will wager a guess and say I bet your back angle isn't much different between your two Roubaixs...but bet the angle of your arms to the handlebars is quite different due to the higher handlebar of the bigger size 58 Roubaix. The only way I will know what would be best for me is do what you did....buy a size 56 Roubaix and set it up close to yours and ride it. I am considering this in fact...and then sell the one I like the least in terms of comfort and fit.
I have ridden the 56 Roubaix and it feels pretty good and quite different from the 58. Maybe a trip to the local Spesh dealer is in order for a test ride. I would like to try either new Ultegra or Sram groupsets as well.
Thanks again.

Jmx, below is a recent pic of my size 58cm 2012 Roubaix SL3 Pro built with Campy 10s, FSA K-force lite seatpost, Kwing carbon handlebar, Ritchey WCS stem: