What different kinds of bike handle bars are there? All kinds welcome, the common and the nameless.
If possible include the pros and cons of the bar
One bar per post
The simplest kind of handlebar, these are a straight bar with grips on the end. Flat bars were traditionally only used by cross-country riders but now you see them in more general application.
Flat bars (image credit)
Flat bars offer more space to mount lights and computers than drop bars. These bars have bar ends attached for additional hand positions. (image credit)
Usually seen on road bikes. Designed to give the rider multiple hand positions, as well as the ability to "tuck" forward, decreasing wind drag. These can be fitted with aerobars for additional aerodynamic advantage.
Drop bars are generally narrower than flat bars, and don't offer quite as much detailed control over the bike on uneven surfaces. Drops are often the bars of choice for longer bike rides.
Drop bars on a touring bike (image credit)
Also see entry Variations on Drop Bars.
Allow the rider to sit upright on a bike while holding the bars. Also known as upright or North Road handlebars, these are common on cruiser bikes and some comfort bikes. They sweep back towards the rider, with grips that point more towards the back than to the sides.
Cruiser bike with handlebars (Photo credit)
(or aerobars) originating from triathlon, but now seen in almost any time trial situation where the racer is alone and not able to ride in a group.
The pros of the design are to promote a static, streamlined position, where the rider cannot easily move but will remain in a aerodynamically advantageous position, thus resulting in a faster ride.
The cons are that this design is often uncomfortable for extended periods. When used on a bike that is then ridden in a group, it can be dangerous, as coming off the bars to use the brakes takes time, and some designs present what is effectively a couple of spikes to the front, which could make a collision with a softer target a worse outcome.
Tri-bars can be 'standalone' bars or installed as an add-on to normal bars. Gear shifters can also be added to allow riders to remain in position while changing gear. Triathletes will often use the space between the hands to place a bottle with a straw to allow for hydration with minimum movement.
These can sometimes be found at the local bike dump cheaply. Some find them quite comfortable, and they allow a lot of different positions.
Although purpose-made handlebars are generally better, it's possible to make a set of bullhorns by cutting drop handlebars and flipping them over.
One of the more interesting bars I've tried is the Titec H-Bar (there are also other brands of H-Bar, as I recall). Insane amount of hand positions. Can be hard to find a good spot for levers and shifters, though.
Here are rebar bars on a rebar bike.
Riser-bars place the rider in a more upright position than completely flat bars and might be better for mountain-bike technical maneuvers such as slow drops to flat (hucking) and just generally lifting the front wheel to clear trail obstacles. (They are still flat handlebars, but are raised at the ends.)
Handlebar width is also important and the trend for mountain bikes seem like they are getting wider. Wider bars give more stability during hairy technical descents, but the downside is that trail side tree clearance is reduced.
Variations in Drop Bars
Note that the links are just representative of the style, not the actual cost. There should be negligible price difference between the bars.
In my case, the ergo bar pushes the palm of my hand away from the levers. This makes it much more difficult to reach the levers (mostly for shifting, although it is at the limit of comfort for braking as well). You could fix this problem one of two ways: buying a set of levers which have an adjustable reach option, or swapping out the handlebars. I'm doing the latter.
There is also the randonneur bar, a drop bar where the middle bar arcs upward slightly at each end, the drops angle outward, and the drop is less severe than the standard design. Designed to be more comfortable for long rides.
A bull horn setup with an add on so that the rider can ride in a more upright position when on the flats. This seems like a good setup when speed is desired some times but the rider also wants to be able to smell the flowers. You can brake from the top by pulling on the rod.
From: Bike snob NYC
Primarily used for racing, these blur the line between bullhorns and tri-bars/aerobars.
First used in 1984 by Francesco Moser's World Hour Record ride.
3T pursuit bars.
Lowered bullhorn bars - add aerobars to these and they become pursuit bars.