Originally Posted by
mulveyr
Depends what you're using the bike for. For my touring bike, I was much more comfortable on a bike one size "too big" than all the fit calculators claimed. For a sportier bike, one size "too small" can be adjusted out.
We're probably going to be in the minority here, but slightly too big (1 cm in a 64 vs. 65 tossup) worked for me too. I'd been riding a 62, and Rivendell's sizing guide put me on a 64cm Atlantis. It's great--but a few months later I got a really good deal on a used 65cm Rambouillet (another Rivendell model), and it's probably a little more comfortable.
As another post noted, though, not a huge difference. By old-school standards, many people are on frames that are too small for them anyway.