I assumed that it wouldn't make much difference in handling if I put a flat bar on a bike designed for a drop bar, It seemed logical that if I ride on the top of a drop bar it should handle similarly to a flat bar. My Trek Domane 4.3 was ridden with a flat bar for 18 months. After battling winds, I decided to get more aero, so I installed a compact drop bar and brifters. That made me remember why I went to a flat bar. Woke up the next morning and decided that I hadn't given the drop bar a fair chance, so I raised the bar and made other minor adjustments. Whammo, the bike felt a lot more comfortable. The biggest surprise came when I rode it. This felt like a totally different bike--almost unrecognizable. Much more responsive, faster, more agile, more aggressive, and a little more twitchy. Suddenly, the bike went from feeling like a hybrid bike (not a bad feeling) to a responsive performance bike. It became a lot more fun to ride. I don't know why changing to a drop bar made such a difference, but I guess you can't beat geometry. I began to understand that a bike is designed to be ridden in a certain configuration, and when that is radically altered, everything changes. Moral of the story for me: "keep the bike the way it was designed."