Sizing-wise – at 6′ 1/2″ I got a 20″ and it’s perfect with an 80mm stem.
If you look at at the geometry, there is very little (I mean the width of a dog end) in reach/wheel base between the 16″, 18″ and 20″. The main difference is Head tube height and, obviously, seat tube.
Personally I think this weird sizing is the frame’s only weakness. I’d have liked to have run a 50mm-60mm stem but that’d be too short for me.
How on earth shorter types get on I’ve no idea – the difference between the 14″ and 16″ is huge then, as I say, the 3 other sizes are kinda the same.
I’d love Brant to explain this one.
Oh, only other weakness is lack of dropper post cable guide.