Is this frame too small for me?
 

I'm looking to buy a second hand bike to do a 2 week tour around a few countries in western Europe. All-in-all we're looking to cover about 350 miles, so nothing too extravagant. I've seen this bike I am really keen for but it's a 56cm frame. I'm pretty much exactly 6 foot and have a pretty even split between my torso and legs, but I do have rather long arms. I know from a conventional road sizing chart that this frame would be slightly too small, but will it make much difference? Would I be looking for a slightly smaller frame because I will want a less aggressive riding style?

I don't know if there is some sizing issues to touring that I'm unaware of, but judging from the details you gave me, I'd say no. 56 is one of the sizes I'd have you test ride if you came into the shop where I work. If it's more comfortable than the other frames you've tried, then go for it.

Too hard to tell, as there are now so many variable, with compact frames, full size, manufactures differences, as above, test riding is the way to go

If the bike is a classic road frame (level top tube) it's almost certainly too small for you. Even if you could use a long seat post, odds are the bars will be too low, and the overall length too short. I'm 5'8" and 57cm frames (level top tubes) a correct fit, with 56cm about the lower limit.

If the bike has a sloping top tube, there's a decent chance it'll be fine. These are designed around the use of a long seatpost, and the bars are higher and probably farther away.

I ride a 55cm frame with a level top tube and I'm 5'10". That's what a professional fit put me on, and it works great. I don't think I could ride a 57cm without compromising my reach, or seat position. That said, the OP is a little taller than I and I won't dispute him if he decides a 57cm or larger is the right size for him. But a 56cm isn't too small, it just might not be what he prefers.

Cheers for all your input guys. If the price is right I'm going to go ahead and get the bike, I can always re-sell and keep my current bike if it turns out to be too small!

For what it's worth, you can always put a long and steep angle stem or one of those extenders on it if you need to. Some people don't like the looks but it would certainly get you through a 2 week tour.