Bike handlebars

Handle bars are awesome, they allow you to control your bike and give girls rides on them. The also make a hell of a mustache. But lets get down to the good stuff. Handle bars come in all shapes and sizes and which one you choose depends on a few factors, your personal preference, whether you are a road, mountian, or hipster fixie bike rider.

Road Bike Handlebars

Road Bar Width

If you are a serious road rider you want to make sure your handlbars are the correct width, roughly the distance between your shoulders.  Starting with the correct width gives you a more comfortable ride.  Road handlebars come in a variety if widths roughly between 36cm and 46cm.  You might want to visit a bike shop to try a few options.  Then you pick whether you want to splurge and get some bad ass carbon bars or just skip the hamburger and get similar results with a set of aluminum handlebars.  Newer road bike bars also incoporate a more ergonimic designs by flattening the top of the bar to rest more comfortably in your hand.  

The Drops

The you've got the drop, and we're not talking dubstep here.  The drop is what makes road bikes so recognizeable, the curved part of the handlbar.  A classic drop is found on most older bikes and puts you in a lowers position when riding in the drop poisition, more aero, but maybe more uncomfortable.  Most moder bars have a shorter drop that is less curved and doesn't make you reach as far.

Clamp Diameter

Dropdown bars vary in sizing depending on the year they were made and the brand. Any relatively recently made bar is going to be either 26.0mm or oversized 31.8mm

Moutain Bike Handlebars

Clamp Diameter

Mtb bars measure either 25.4mm or 31.8mm for oversized bars. The handlebar and stem have a symbiotic relationship so you need to take them both into consideration when you are thinking about upgrading one or the other or both. I'm trying to think of a funny metaphor that I could throw in here, but I can't, put one in the comments.

Size	Description
31.8	Common clamp diameter for modern oversize bars.  Interchangeable mountain and road use.
26.0	Formerly the most common size for road bars (previous to the oversize 31.8 clamp).
25.4	Formerly the most common size for mountain bike bars (previous to the oversize 31.8 clamp).  Also used on some Japanese and Taiwanese road bars (Nitto for example).