Originally Posted by
Lemond1985
It's probably worth noting that a lot of pros ride what look like pretty small frames, with great success. World champion Peter Sagan is 6 feet tall also, and his frame can't be much bigger than 54-55 cm. You can't argue with the success he's had.
There are advantages of having a smaller frame underneath you, I think it's referred to as "flick-ability". Good for climbing and sprinting, where you are throwing the bike around a lot. Lighter too, but that's not the main reason.
There's no trick to making a too-small frame fit, just get longer stems and seat posts. I like my frames on the larger side of the range I can ride, but there are lots of advantage of going small, and no reason someone that wants to can't make it work for them.
Pros ride smaller frames for numerous reasons. I've never seen it expressed, but a couple of obvious ones are lighter frame weight, increased handlebar drop and, as you alluded to, shorter wheelbase. There's some old photos of Tom Boonen in the early 10s riding a Specialized that looks like a kids frame under him.
I test rode my CAAD10 in 56 and 54cm sizes. I would normally ride a 55ish. What actually sold me on the 54 was that my thighs were rubbing on the top-tube of the 56.
My steel bikes have more conventional top tube diameters, so I don't have that issue on 55cm sizes.