When it comes to mountain bike handlebar, it is commonly being narrowed down to 2 types which are Flat and Riser bar. Flat bar (shown in Figure 1.1) is standard handlebar equipped on mountain bike and is a nearly-straight tube that made of different materials such as aluminum and etc and some of them are slightly bent toward the rider.
Figure 1.1: Crank Brothers Cobalt 3 XC Flat Bar (7075 Aluminum £43.33, Evancycles)
Riser bar (shown in Figure 1.2) is kind of a variation of the flat bar which both outer sections rise from the center clamp area where the connection point with stem by about 15 to 50mm. It has been widely used in downhill mountain bikes (shown in Figure 1.3).
Figure 1.2: Easton EA50 Riser Bar (Taper wall £26.66, Evancycles)
Figure 1.3: Downhill Bike Equipped with Easton Riser Bar
Handlebar is an important accessory as it offers better control that helps for positioning for balance as well as easier breathing that can increase the pleasure of riding. 3 major factors to put into consideration while looking for your favorite handlebar:
The first thing to understand is that the bar width is closely linked to the stem length. While you add bar width you should also consider reducing the stem length. For example, if you have decided to go from a 620mm to 660mm handlebar, and you have a 90mm stem, we would suggest reducing the stem length to 70mm that can center you better over your bike. At the same, please note that you would need to choose a handlebar that closely matches the width of your shoulders.
Wider handlebar gives you better leverage of control especially riding downhill compared to shorter handlebar but it also tend to the possibility of losing more energy while you are getting exhausted riding uphill when you wanted to ensure to ride in straight line, shorter handlebar comes in handy in this scenario which helps to focus on putting power on your both legs to keep on spinning.
In the market, most of the handlebars are made of either aluminum, carbon fiber or scandium. Those materials are stiff and reliable, but weight of carbon fiber and scandium is normally lighter. However there have been great discussions that carbon fiber exposed to shorter life span and also higher possibility to crack due to accident. Some of the handlebars are tapered and even butted to strengthen it especially for those downhill bikes that carry more impact.
As mentioned earlier, scandium and carbon fiber are way lighter than aluminum. However, it could double up the cost as well. Anyway, the weight saving is normally not more than 100 grams for the same width of handlebar. Therefore you need to justify it if your money is worth for such a little weight saving.
To me, I will go for aluminum with less money spent and it does convince me of the reliability without much worried about the life span.