The sizing info on Giant’s website for the TCR makes sense, but doesn’t. I stand 5’9” w/ 80.5 cm inseam which by their hieght chart that puts me on a Med (5’6” to 5’11”) frame. On the inseam side it tells me that I would use a small (51cm,53cm,55cm).
i’m 5’9" and bought the medium. not sure about my inseam, but i had to ditch the aero seatpost for a standard one because the aero would not go low enough for me- more than likely why they dropped the aero post. it was only by a few mm, but it didn’t work. go with the medium at your height. you’ll be better off running a shorter stem and lowering the seat than putting an unusually long stem on the small.
“In theory” you could order the aero seatposts in different lengths so you could get lower. I guess it’s a moot point for 2004.
I looked very closely at the TCR Composite. I rode a friend’s bike, and found the ride to be pretty spectacular, though his bike didn’t fit me. I went to one of my local shops and talked about the bike at length with the owner who had fit my friend on his bike. He felt that my legs wanted a large, but my torso wanted a medium. In his opinion, the best option was to go with the larger frame with a short stem, but the handling might be affected depending on how short the stem was. I ended up going with a different frame.
The issue you seem to have is a bit different, top tube may fit on the medium, but the seat may need to be low. This should not be a problem with the compact geometry (read - lower top tube), but I am not an expert by any stretch. I would go take a look and take one or two for a spin.
I’m half way over 5-11. I just finished riding my sweet sweet riding med giant composite. I could have gone with the L but IMO it is easier to make a smaller bike frame larger than a larger bike frame smaller. I have a 120 stem and 9 inches of seatpost showing on my med.
I’d go with the smaller frame again if I had to do it all over. Try to ride the med and L then go with which one fits best and your most comfortable on.
I just bought a TCR aero size medium. I’m 5’8" and ride with my seat 28.5in from top of seat to mobb. My wife rides the small frame. I tried it first and it just did not feel right and I had to borrow an extra long seat post to get the seat high enough.