Originally Posted by Dunbar

Effective top tube (ETT) length is what you want to focus on. I'd say go for the 55 or 58 depending on what sort of riding position you want and your cycling inseam. The 58cm will give you more adjustability in terms of bar height relative to the seat. Just make sure the standover height on the 58cm isn't taller than your cycling inseam measurement. The 55cm with a 130-140mm stem will place the bars lower and give you a position that is very close to your 21" Coda.