So everybody always talks about frame sizing like there is some ideal magical perfect fit. I’ve never really felt like it was a huge deal to have precisely the right size. I’m 5’11" and would probably have something like an 56 square ideal frame size.
But you know what? On my 54cm frame, I have a little more seatpost sticking out, and on my 58cm frame I have a little less seatpost sticking out. My stems are sized accordingly, and it’s no big deal.
I can’t argue that there are limits to generically sizing frames. And that if you’re racing then small differences could be comparatively large. And if you’re mtb’ing you probably don’t want to ram your nuts repeatedly into the top tube.
But for most of us, it doesn’t seem like a size or two or three off of ideal really matters after swapping to a smaller or larger stem. Not only that, but depending on how you like your saddle to bar drop, a size larger or smaller can help out hugely with that as well while avoiding obnoxious stem setups.
Correct bike fit is easily the most important thing on a bike. People have budge room in frame sizes from ~3 or 4cm, after which your bike is too big or too small. I think the only people saying you must have an EXACT, PERFECT size number are custom framebuilders and those who buy from them.
i remember going to a lbs to test out a steamroller a while back. the sales dude lectured me about the angles of your legs and muscles to the cranks and efficiency or something when i grabbed a random sized one. i’m sure there’s some truth to whatever he was saying but i’m also sure that a lot of it was him trying to impress me with his bike knowledge.
also, oddly enough he was really trying to sell me a langster instead.