hubcyclist

So I have a mid 90's bike, a 56cm frame. I like the bike for the most part, but it might be a bit more aggressive than I really want at this point. I have my saddle at 78.5cm and the drop between the saddle and bars is 5in (maxed out with the spacers using a threadless quill converter). Apparently, the stack is 53cm, the head tube about 13.5cm. Leaving aside stem options, if I were to look for a modern frame, would the bigger stack (like I see the cannondale caad8 has 57.3cm stack for the 56cm frame) and/or larger head tube be the areas where I would have the slightly less aggressive position? I am going to race in October and next season, but I like to do a lot of long rides as well. Anyway, just wanting to understand geometry a bit better so I know what I'm talking about if/when considering other options.