3T's sculpted track handlebar, "The Sphinx" (c) 3T
Choosing handlebar width is easy - nearly a no-brainer. But beyond that, what? A quick Google search turned up this paragraph from a fairly detailed article on fit written by Peter White:
Handlebar width (road & ATB) and drop for road style bars
A few brands of drop style bars come with a choice of how much lower the drop section of the bar is from the top. Unless you are a track sprinter or a criterium racer, you don't need the very deep drop bars. Most bars come in a selection of widths. Most people seem happiest with their hands positioned on the bar at about the same distance apart as the width of their shoulders, so that your arms are roughly parallel when reaching to the bar. When determining stem dimensions, try the different bar widths available, starting with one that's the same as your shoulder's width. Then see which works best for you.
Again, width is almost a no-brainer - for most people a handlebar close in size to the distance between their "shoulders" is the best choice. But then what? Think of all the variables involved in the relationship between the rider's hand position and their ability to control the bike, operate the brakes and the shifting mechanisms and feel good doing so...
Manufacturers don't seem to offer much help, either! I've used the Deda Newton (anatomic) bar in width 44cm (measured by Deda outside-to-outside; in Cinelli, for example, I'd be a 42) for the better part of nine years. My Pinarello came with a more traditional round bar with shallow drops. The reason that I most like the Newton, and the factor that has kept it on all of my bikes for nearly a decade, is that it allows for the creation of a fairly flat, consistent platform at the junction of the "STi Lever" (aka shift/brake lever) and the bar - the hand position described as "riding on the tops" or "riding on the hoods." (I'll post a picture of what I'm talking about soon.) This certainly wasn't possible with the stock bars that came with the Prince. I did, however, like the fact that I had a variety of positioning choices while in the drops with the stock bars - something that really isn't possible with the anatomic shape of the Newton. I know Deda came out with a new bar based around what they call the "Deda Rapid Hand Movement (RHM) design initiative" but can I still create that level junction like I can with the Newton anatomic? Do we even have a language to talk about this?
The answer, of course, is who knows, because Deda doesn't discuss this in its marketing literature, and Competitive Cyclist's product verbiage doesn't include much on the topic (see below). Why aren't we talking more about different handlebar options? Or are people discussing this, and companies focusing on it - and I just can't come up with the info via Google. Thoughts? I've turned-off comment moderation in hope that we can get a discussion going on this topic. And please, by all means, if there is some rec.bicycles.tech archive or forum with a matrix comparing all of the market's current handlebars in scenarios with each of the three main STi lever shapes - Shimano, Campy and SRAM - please let me know.
2010 Deda Elementi Zero100 Alloy Handlebar product description from Competitive Cyclist:
This bar is an iteration of RHM that appeals to traditionalists. The drop is a fairly round curve, though the radius of the curve is tighter at the top and increases as it goes down. It isn't quite a traditional even radius that you'd find on Deda's deep or shallow traditional-style drop bars, but it is still fairly round. Like all Deda road bars, the Zero100 can have aero bars mounted on the center section. Deda only recommends use of their own aero bars, but others can fit. Deda would prefer people use Deda stems with their bars, but the warranty isn't contingent on the bars and stem being from Deda. They also say that even though Deda measures clamp area of the center section of their bars as 31.7mm, it is essentially identical to other manufacturers' 31.8mm (save manufacturing tolerances). Both are 1.25", just Deda takes the metric fraction 31.75mm and rounds down, while everyone else takes the same fraction and rounds up. The Zero100 has 128mm of drop and 75mm of reach. Both are measured outside-to-outside. The bar comes in 40, 42, 44, and 46cm widths, measured outside-to-outside..."