The whole drop handlebar size thing mystifies me. The measure your shoulders method is merely a start, as I know a lot of riders who use a size down from what the measurement would indicate, and they like and prefer them to the slightly larger ones that the measurement says they "should be using". I'm included in that. I use 42s when my measurement indicates 44 should be the size. I've used both long enough to know I prefer the narrower ones. I realize complete bike sellers need to put something on their bikes, but the sizing guide most seem to use seems a size off to me in general. I don't think a lot of people out there need 44s. Some shops will swap out bars on a new bike for free, some won't. But if buy a new bike and something just doesn't seem right with the bar width, buy a cheap one in a different size and try it out. You may prefer the other size (which is probably going to be smaller).