While many riders and bike shops advise against using flat handlebars for touring, the opinions on the other major styles of handlebars vary. Drop bars are particularly popular for touring, but the geometry of trekking or mustache bars may be more suitable for your bike and riding style. Be aware: road bikes typically accommodate only road handlebars and stems, while mountain and hybrid bikes can take either mountain bike components or road bike components, with some modifications.
Drop bars are the classic road bike handlebars. They clamp into the stem in a straight section, then curve away from, down and back toward you. Drop bars are popular for touring because of the many hand positions they allow and the aerodynamic posture you can adopt while using them. The ability to shift position can mean the difference between needing to take a break and being able to make it to your planned lunch stop. Drop bars are not normally used with mountain or hybrid bikes, because the frame style encourages an upright position that the drops do not support. However, they may be compatible with some modifications. Drop bars can take only road bike brake levers and shifters.
Trekking bars are more common in Europe than in the United States. Unlike drop bars, trekking bars or butterfly bars, are flat. They curve away from and to the sides of the rider for a more forward hand position, then curve back toward the rider, and then toward each other to form a flat section near the rider, ideal for a more vertical sitting position. Trekking bars are usually mounted parallel to the ground, but can be mounted at an angle if preferred. Trekking bars accommodate mountain bike brake levers and shifters.
Mustache bars are similar to trekking bars except that the ends do not curve back toward each other nearest to the rider, but simply end. As a result, they have one fewer hand position than trekking bars, lacking the near and more upright reach. Mustache bars accommodate road bike brakes and shifters only.
Flat or Riser Bars
Rivendell Bicycle Works and Bicycle Touring Guide advise against using flat or riser bars for touring on paved roads because of the small number of possible hand and arm positions and the unergonomic wrist-down position. If you must use flat bars, get bar end grips and change your hand position frequently. Bicycle Touring Guide says that flat or riser bars may be suitable for off-road touring, where terrain is a greater factor in comfort than wind resistance.
If you replace the handlebars on an existing bike, check that the diameter of the handlebars matches the diameter of the stem on your bike. If you are changing from mountain bike handlebars to road handlebars or vice versa, your stem may be the wrong size and need modification or replacement. Your brakes and shifters are designed to work with a certain type of handlebar and may not be compatible with a new one. If you need to raise your new handlebars, cyclist Tom Deakins states that you may also need to get longer shifter and brake cables and cable housing so that the cables can reach the new height.