Handlebars are perhaps the single most important point of contact on a bike. However, it can be easy to overlook this crucial element and its impact on bike fit, steering accuracy, and comfort on the bike.
The first thing to realize is that mountain bike handlebar size and shape can be a personal choice. What might work for one person might not work for another. And as a part of the bike fit equation, what makes for a good comfortable fit on one frame might not work as well on a different bike since the geometry and sizing will be different. The main thing to understand is that it might take a bit of experimentation with your setup to find the ideal sweet spot.
Mountain bike handlebar geometry
No, this has nothing to do with your favorite watering hole, though geometry can get complicated after a visit to your local hostelry. When it comes to handlebar geometry, there are two main numbers to consider: rise and sweep.
Rise is essentially the height differential between the center of the bar, where it attaches to the stem, and the center of the 22.2mm diameter just after the taper and transitional bend. Mountain bike handlebars are typically configured with zero rise (flat bars) all the way up to 100mm (roughly 4 inches). Bars with 100mm rise aren’t very common anymore, so these days, “high-rise” bars are usually in the 40-50mm range (about 1.5-2 inches).
Choosing the right amount of rise usually comes down to rider position on the bike. If the cockpit feels too low (for a taller rider, for example), a riser bar can get grips up into a more comfortable position. A riser bar will naturally have a bit more flex than a straight bar, assuming both bars are made of the same material and have identical diameters and widths.
Flat bars tend to be found on XC-oriented bikes while riser bars are used on more gravity-oriented setups. Since gravity bikes are optimized for riding downhill, a riser bar keeps the rider’s head and torso slightly higher on the bike for better control on the descents. Finally, some riders just prefer the look of one style over the other, so again personal preference plays a big part.
After the rise, the next thing we need to think about is bar sweep. There are two measures of sweep: upsweep and backsweep.
Upsweep is the vertical angle of the bars at the grip. Upsweep does affect the overall rise of the bars, and is a separate measurement that affects rider comfort more than anything else. Most bars, if they list an upsweep measurement at all, will fall between 4° and 6°. This tends to provide a good, neutral wrist angle for riders.
Backsweep refers to the angle at which the bars swoop toward the back of the bike. This angle can range from 0° for a completely straight bar to 45° for a specialty bar like the Jones H-Bar. Again, sweep comes down to rider comfort and preference ahead of any other considerations like performance.
Thankfully, mountain bike bars come in just one width at the grip: 22.2mm. This means grips are interchangeable with any bar on the market. When it comes to the stem clamp, that is a different story. The most common diameter is still 31.8mm, but older bars can be 25.4mm.
More recently an oversize 35mm standard was introduced by Easton that promises even greater strength and stiffness. With a larger clamp area, the bars tend to be stronger and stiffer. Larger clamp diameters also provide increased surface area for the stem connection, resulting in lower clamping pressure requirements, which is a good thing for carbon bars.
However some riders prefer the flex and lower weight that is associated with 31.8mm bars. The comparative increased strength and lack of flex of the 35mm clamp diameter bars can sometimes lead to a harsher ride feel than the narrower diameter bars.
Bottom line: if you’re upgrading your bars but keeping your stem, make sure the new bars will fit your stem clamp diameter. If buying both, ensure they will play nicely together.
For the past several years mountain bike handlebars have been trending wider. The wider, the better.
Now this is actually true for most modern riders, as wider bars slow down steering input for added control, especially when paired with a short stem. The longer a lever, the easier it is to move a weight, and since handlebars are a lever, the same rules apply.
Wider handlebars can even make breathing easier on the climbs. (Think about taking a deep breath with arms wide vs. arms crossed in front of your chest.) Now the crucial thing is to have a bar that is wide but not too wide. A handlebar that is too wide will stretch a rider out on the bike, ultimately limiting the range of potential motion on the bike. A bar that is too narrow has the opposite effect; while it increases the rider’s range of movement, it does make steering heavier and less stable feeling.
Beyond control considerations, wider bars can make navigating dense forest trails more difficult. But also keep comfort in mind. If you have short arms, you may not want the widest bars available, even if you are a super aggressive gravity rider.
These days, mountain bike bars are available in widths ranging from less than 600mm all the way up to 840mm or more. When shopping for mountain bike handlebars, it is important to note the width of the bars but keep in mind that you can always cut the bars down. Unfortunately you can’t safely add width to a set that are too narrow to begin with.
Cross-country riders will usually prefer narrower bars compared to trail and downhill riders.
Now bar material is conventionally thought of as a binary question: you either run aluminum alloy, because you’re not rich or you don’t trust carbon; or, you run carbon, knowing those fears of a bar failing are unfounded and you like a bit of black glossy bling. But these are not the only options available on the market. Titanium and steel bars are also on offer for the discerning and offbeat rider.
Aluminum bars are generally the least expensive but are heavy. Titanium bars can be more expensive than carbon, and are generally heavier than carbon as well.
Titanium offers the least “harsh” ride feel in terms of impact and vibration, with carbon bars providing some forgiveness as well, and aluminum bars being the stiffest and harshest. Steel has some natural spring to it and offers a feel that some riders prefer.
Each of these four materials offer various and differing amounts of these key characteristics:
- Vibration damping
In addition to these characteristics, there is also fatigue considerations, a specification seldom listed for a bar. But the number of hours of expected use is something to consider.
Some aggressive riders shy away from carbon bars, thinking they’re not as strong as aluminum. The fact is, carbon bars are often as strong, if not stronger than their aluminum counterparts. But aluminum fails in a much more predictable manner (bending or yielding), which is significantly less dramatic than a carbon bar snapping in combat.
The crucial factor for all bars is to ensure they are correctly installed with the proper torque, which will help prevent a catastrophic failure. It is also vital to inspect and perhaps replace any bar that has taken a mighty pounding in a bad crash. If in any doubt, see you local bike shop mechanic and get them to inspect or fit any new bars for you.
Most mountain bikes utilize a standard straight bar, but these days, mountain bikers are experimenting with other shapes like the Jones H-Bar and road-style drop bars. Many of these choices are based on extreme use cases like bikepacking and ultra-endurance riding where riders want to utilize multiple hand positions throughout the ride to avoid fatigue. In general, these types of bars trade comfort over trail handling
So there you have it, the 101 intro to mountain bike handlebars. Let us know which bars and widths you’re running in the comments.