I am wondering if a Merckx Team SC sloping frame that is 48cm(c-c) seat tube and 54cm(c-c) effective top-tube will fit a guy that is 5''10' and has an inseam of around 31.5' well?

http://www.competitivecyclist.com/za/CCY?PAGE=BRAND_GEOMETRY&BRAND.ID=13

This size should be quite close, but I suspect your cycling inseam is more than 80cm, if not, you've got short legs and a long torso. Check out the Colorado cyclist website for one method of measuring cycling inseam. Be sure to apply saddle like pressure, with no bulky clothing in the way.

www.coloradocyclist.com/bikefit

just did a measurement... actually, I am 176cm in height and my inseam is 82cm... anyway, i believe that it is 54cm eff top tube as stated from the merckx website.. the distributor that i called up also said its 54cm...

The TT length is clearly 55cm, the c-c frame size is equivalent to a 54cm.

http://www.eddymerckx.be/bike/technical.jpg

82cm is still on the short legged side. The 48 sloping would be plenty tall, but not any too long.

Interestingly, the 45cm actually has a 1mm longer reach than the larger 48cm, due to the difference in the seat tube angle. Reach is the TT length minus the setback. Either of these frame would require the same length stem.

Ultimately, the decision between these two should be based on saddle height and handlebar height. The head tube is a lot taller on the 48cm. My inseam is 1cm more than yours (but I'm 7cm shorter) , I have a 71cm saddle height and the 48cm would be a bit too tall for me.

my 48cm sloping team sc has a 55 cm toptube, and a setback of 15.8. i'm 5-9.5 with short stubby legs and a longish torso. i could ride either the 45 or the 48. i chose the 48 because of it's longer headtube. i use a 120mm 84 degree stem.

I'm looking at a sloping Merckx, but haven't seen one. Thanks!

sorry for the crappy photo ... best i've got available:

What's your head tube length?

Thanks!