Looking at picking up a NOS Optimo (2006 I believe, non-disc), but it's a little bit of a drive, so I want to suss it out ahead of time.

I'm 6'0" on the dot, fairly normal shaped, and currently ride a 56cm Kona Jake that is just a bit on the small side. Looking at the 56 vs 58cm Optimos, looks like they run a bit bigger than Konas? Any experience with this?

Any input is appreciated.

C-dales cross sizes are sorta goffy.

56 at the biggest. I'm 5'-11.5" and ride the 54 which is perfect for me using a 110mm stem. A local expert/pro rides the 54 also and is 6'. Like me, he says the 54 is a tad on the small side, but the 56 is huge in comparison. Hes also sponsored my C-dale in cross and mtb.

I'm 5' 10" with a 32" inseam and usually ride a 54/55 road bike with a 110 or 120mm stem.
On my 06 Optimo I ride a 52cm with a 110mm stem and fits well.

I'm 5'10 with a 30" inseam and I've been racing a 54cm Optimo with a 110mm stem. Never felt like it was too big. Although I did switch to 170mm cranks for my short legs.

I wish people would post photos of their bikes (the usual profile shot) when these threads come up, i.e. "I am 5'10", 33" PBH, and here is a photo of my 54cm Optimo."

I ride a 56cm 2005 Optimo and I'm 6'1" w/ 35 inch inseam. I've got a shorter torso so I have to live with more seatpost showing than normal in order not to be too stretched out, especially for cross.Personally, I rather be more upright on a cross bike. Look up the geometry on Cannondale's site (they have an archive for older models) and you'll see how they size their cross bikes.

I ride a 56cm 2005 Optimo and I'm 6'1" w/ 35 inch inseam. I've got a shorter torso so I have to live with more seatpost showing than normal in order not to be too stretched out, especially for cross.Personally, I rather be more upright on a cross bike.A smaller frame actually means you are less upright.

When I ride a frame with a shorter top tube(my cross frame) & all other things being equal, I have less distance to reach the bars. My torso is then more vertical( I sit more upright) than on my road bike with a longer top tube. As for cross a good primer for setting up one's bike can be found here:

cycle-smart.com/Articles/find.php?search=31

When I ride a frame with a shorter top tube(my cross frame) & all other things being equal, I have less distance to reach the bars. My torso is then more vertical( I sit more upright) than on my road bike with a longer top tube.The problem is that all other things are not equal; you're using 2cm more seatpost, which moves the saddle up and away from the handlebars, which is contrary to the whole point of having a shorter top tube. (Another way of picturing this is that the headtube gets shorter, moving the bars away from the saddle.)

Suppose you happened to know that your "perfect" bike was 58cm seat tube, 56cm top tube, and 12cm stem, and the stock frames available to you were:
A) 58cm ST, 58cm TT
B) 56cm ST, 56cm TT
You'd have two options to match the "perfect" setup, one would be to use a 10cm stem with frame A. The other would be to use two extra stem spacers on frame B (provided the fork hadn't already been cut) or use a riser stem, or combo of the two. In both cases you are fiddling with the stem but one solution is more elegant.

Point well taken, pretender. I totally agree, your scenario would result in the more "elegant" setup (ie traditional look). I stated what worked for me as to what gives me the more upright or vertical setup with regards my upper body. Whereas the 2cm more of seatpost showing only resulted in slightly more distance on the horizontal plane. It does though yield more "drop" but that was taken care of by flipping the stem for a positive rise. Now, with my stem flipped upwards I reduced my drop but due to the shorter top tube I now have less reach or distance to the bars . Keep in mind that the Optimo has a top tube sized longer than the seat tube so had I gone with a 58 cm to better match my inseam, the top tube would of been 59cm and I would of required a much shorter stem to give me the upright stance.

So as you suggested, had my ideal setup been a 58cm seat tube, 56cm top tube, and 12cm stem ( and I assume you meant road setup) the Optimo would of given me a 58cm seat tube, 59cm top tube and I would have had to replace the stem with a 90cm stem just to get it back to my ideal setup(again,assuming this a road "ideal") then shortened it some more to give me less reach or distance to the bars for cross. That's why I personally went with the smaller size frame.