Thanks for the link bro. Yeah that makes a little more sense looking over this chart. It looks like Giant's suggestions for frame sizes go along the lines of indicating that these frame sizes indeed run a little bigger than other brands. I'm 5'10" and according to Giant, they spec 5'10" to be right in between the 50 and 53.5. That being said, perhaps I don't need to look into the 55.5.