Originally Posted by
link0
Even though height is not by itself a perfect indicator of what frame size you need, a 56 is almost certainly way too big for you. Most men 5'8 in height will be on 50-54cm frames. If you have longer legs and a shorter torso than average, you can go with a slightly smaller frame. The opposite if you have shorter legs with longer torso.
The length of the top tube should somewhat correlate with your torso length. Standover height isn't very important as long as you have at least 1" of clearance for safety.
I'm certain you will fit far better on that 53cm frame.
My brother is 5'6" and rides a 54cm Trek frame. I don't know how Kona frames are measured, but Trek frames are measured to the top of the frame (which is 3cm higher than traditional C-C measurements). He also prefers a long top tube and does have comfortable clearance over the seat tube. This is a traditional straight frame, not one of those slanted top tube frames. Bottom line is there are a lot more factors to consider when sizing a bike than just your height.