Don't longer top tubes make you more aerodynamic?
I saw a Bianchi Volpe listed by someone as a "touring" bike on Craigslist and felt incensed. How dare that person damage my perception of the Volpe as something faster, quicker, and more armstrong than a hipster touring rig. I decided to actually dig through the geometry of several road, touring, and crossbikes to determine whether there were any real differences which would account for this perception that cross and road bikes are faster than touring bikes.
What I found was that everything is basically the same discounting a difference in 1 degree or centimeter here or there. The only noticible differences are that touring bikes are a lot longer via the chainstays and road bikes are a lot shorter in the top tube. Agreed? This brings me to two questions:
1. What about a longer wheelbase (longer chainstays) makes a bike less "agile" or "crisp" like I keep reading about here? I have a couple thousand miles of experience on a Poprad, so am not a complete noobie, but when test riding a Redline Conquest directly after a Long Haul Trucker I don't really notice a difference in how quick I can turn the handlebars. I haven't tried turning around in small spaces, but don't figure that anyone other than the racers on the board have either. So is this so-called "agility" and "twitch" a product of more geometry factors than just wheelbase? If so, what?
2. I was surprised that road bikes generally have shorter top tubes than cross bikes. Why? Wouldn't a longer tube stretch you out more, creating a more aerodynamic position for the rider? Shouldn't road bikes have longer tubes than bikes designed less for speed and more for comfort instead of shorter than touring bikes?