Hi-I currently ride XL size TCR Adv Pro 0 Disc and entertaining the idea of getting a Tarmac SL7 at some point. I have gradually lowered my position over the past couple of years and still want to go a bit lower. However, I ran out of spacers and don't want to use a negative angle stem (let's just say for aesthetic reasons).

XL size TCR and SL7 61cm are quite similar geometry; TCR has a slightly lower stack and reach #s are almost the same. TCR has a more slack seat tube angle. Same with the head tube angles. I attache the geometry table below. I had to measure some numbers myself since can't find them on Giant website. I am 6-4 and 175lbs. My inseam is ~35''



When I go one size down to SL7 58cm I only lose 7mm of reach. 58cm SL7 has a 73.5° seat tube angle vs 72° for TCR which puts my body o bit more over the BB. This translates into a ~21mm forward position on the SL7 but since the SL7's seatpost has 20mm offset the end result is close to no change. (at least this is my uneducated assumption, I welcome comments if that's the case or not)

Stack numbers are 581mm vs 595mm for SL7 and TCR, respectively. This is perfect because it gives me plenty of stack height to adjust to the new fit. Also, seems like SL7's BB height is a bit lower than TCR's. I'm guessing this should also lower my center of gravity and improve my descending and cornering.

Again here I am looking at the bike picture. I appreciate comments on how to approach this purchase and what I said above makes sense. Is any fellow TCR owners here buying SL7? Thanks all.