Originally Posted by Newspaper_Nick

Here is something you should take into consideration while making any kind of flatbar to dropbar conversion. Flatbar bikes and dropbar bikes have different stack/reach lengths, even within the same frame size. This is done to compensate for the longer reach of the dropbars. On flatbars, you put your hands to exactly where the stem connects to the bars, or if you are using an angled bar, your hands may even be behind the stem itself, which gives you a more upright position. On dropbars, your hands connect with the bars where the brifters are installed which is "further ahead" of the stem itself like 90% of the time. That is because you have to install the brifters over the bend of the dropbar, you can't just put them where the flat portion of the dropbar is.

So when you purchase a flatbar bike that fits to your body geometry in terms of size, and try to turn it into a dropbar bike, your reach extends to uncomfortable levels. For such a conversion, i suggest you to buy a bike that is "one size smaller".