OP....
basically your observations and btw, you are well written...a cut above on the 41...are conflating two things. First let me say, I know a lot about fit Basically you are making your judgment based upon which bike fits best over and above what separates the performance of each bike. This is quite common and a newb mistake. Basically it takes 3-4 good road bikes, a couple of pro fittings and a couple of years riding to begin to understand fit…things like saddle setback…what drop is best…even shifter position on the bars…or even dimensions of the handlebars in terms of reach and drop…what length cranks and ideal ratio of top tube and stem length. You haven't arrived at this pt....no fault..just lack of experience and why you are here. So you are are considering a pretty high end carbon bike without understanding your best fit. You don’t know what stack, reach and sta would work best for example. But here is the point. Either the R2 and Tarmac can be made to fit identically. The stack/reach/sta for both bikes isn’t that far apart but they ARE different and a different stem length and perhaps even riser or negative rise stem maybe required for preference on frame size which affects sta on the Tarmac…not on the Cervelo which are all 73 deg…and top tube length.
Another example…unless you are testing a 56 in either bike with 130-140mm stem, you are with the wrong fit as 6’ tall with long torso and long arms. So if you are testing with 110mm stem which comes std. on each bike, you are riding cramped which is no good for the performance fit you prefer. That is why the 58 works better. But you may prefer a 56 with your short legs because of your low saddle height and no need for a tall head tube. I am built exactly the opposite of you as a data point and have to have a 58 because of my long legs to get the head tube length I need such that I don’t run much drop. But for you, a 56cm with long stem makes more sense because of your low saddle height and better head tube length to not get your bars too high.
Both the R2 and Tarmac are superb bikes…but different. The Tarmac is a bit racier. This may or may not fit your preference. The R2 is a racey bike but with onus more on comfort or an all arounder. For some that maybe more like kissing your sister and which appreciate the edge of the Tarmac which btw isn’t too sharp as the Tarmac is a very friendly race bike.
A last note and more on a whimsical level you may appreciate. Do not buy a bike that you don’t LOVE the color…or shape. You must love the color and shape of the bike to be totally smitten. For example, I love the Cervelo in Red and even in white. But I am more a Specialized guy because I prefer their design decisions…I prefer their geometry, bottom bracket design and std seatpost…the R2 having a std. 27.2mm post as well…an important and often overlooked factor.
And finally...a suggestion. Save 1 grand and test a new Specialized Allez…which is an AL Tarmac…or a CAAD 12 with the groupset of your choice. Reason is…you need to learn more about your fit and better understand your best target for Stack, Reach and sta as it relates to saddle setback and your preferred fore/aft position on the bike for weight on your hands based upon bar height preference and even related to your watt output and typical ride duration. Saddle setback also affect distance to the handlebar for a given top tube length. A good fit should start with balancing a rider’s weight relative to the bottom bracket centerline based upon a given crank length target. Reach to the handlebar and handlebar height is based upon this saddle position.
Good luck
Last edited by Campag4life; 08-01-15 at 05:11 PM.