Mountain bike geometry has changed by leaps and bounds in the past five years. The change from high and tight to low and slack geometry has been accompanied by a move to wider handlebars paired with shorter stems. Here’s what you need to know before upgrading your cockpit.
Why we’ve gone wider
Wider handlebars can give you more control. You can think of this as an athletic stance for your arms, a wider position helps to stabilize your steering and gives you more leverage — this can be very important when it comes to handling today’s slack trail bikes as well as many 29ers.
Wider bars can also slow down steering, which can be a positive or negative, depending on your preferences.
The increase in handlebar width has been accompanied by a decrease in stem length. This is done to keep your weight centered over the bike.
Like most things in life, handlebar width is best approached with an eye towards moderation and practicality. If your trails are very tight, heavily wooded, and lack high-speed sections that require stable steering, a wider a bar may be a hindrance.
If your handlebar is so wide that you are riding with your arms extended and your elbows locked you will find it very hard to react to obstacles.
Likewise, if you’re slight of frame with narrow shoulders, wider bars may cause discomfort.
Honing in on handlebar width
Thankfully, there’s an easy way to figure out what width that will work for you. Assume a push-up position the floor and make note of how wide you place your palms on the floor. Measure this distance from the outside of one hand to the other, this will give you a good starting point to find your preferred handlebar width.
When in doubt, buy a wider bar than you need and cut it down to suit your needs. And remember: test the width many times, measure twice and cut once.
Materials and design
The majority of today’s mountain bike handlebars are constructed from aluminum and carbon. There are some titanium options available. Steel handlebars are generally reserved for low-end models and some custom creations.
As in frames, you can't say which material is 'best' because design and manufacturing make more difference to the strength and durability of a bar.
If you’re keen to keep the weight down, carbon is generally the way to go. If you’re less worried about grams than price, alloy bars often have the advantage.
Rise and sweep
Handlebar shape is often described in terms of rise and sweep. Like width, these are critical dimensions to consider when buying a new bar, as not everyone's arms, wrists and needs are the same.
‘Rise’ is a measure of how high the ends of the handlebar are above the portion of the handlebar that’s clamped to the stem. Handlebars range from zero to several inches of rise.
Cross-country riders may prefer a bar with low to no rise to maintain a low and aggressive stance. Trail and downhill riders may prefer a handlebar with more rise to put them in a better position for descending. Rider height will also play an important role in determining how much rise you prefer.
Sweep, also referred to as backsweep, is a measure of the angle the ends of the handlebar relative to the center. Sweep is all about personal preference.
If you’re a rider who prefers an aggressive, over-the-front position, you may prefer a bar with less sweep. Conversely, riders who tend to ride with a rear wheel bias often gravitate to a handlebar with more sweep.
Before buying a new bar. Experiment with handlebar and stem positions. A slight tilt back or forth on a riser bar can make a big difference in the position of your wrists/arms, and in the way the bike feels and handles.
Mountain bike handlebars can be found in three different clamp diameters: older mountain bikes often have handlebars with a 25.4mm clamp diameter, while modern mountain bikes use 31.8 or 35mm diameter clamps.
If you’re replacing your handlebar but keeping your stem, be sure to purchase a bar with the same clamp diameter.
Trim for the win
Let’s say you find a bar with rise and sweep that you love, but it’s too wide. Thankfully, handlebars are one of the easiest components to customize. Both carbon and aluminum handlebars can be cut down.
Carbon bars should be cut with a cutting guide and a hacksaw with blade that has at least 24 teeth per inch.
Aluminum bars should be cut in the same manner and the edges should be finished with a file to ensure they are smooth.
Whether you decide to buy a carbon or aluminum handlebar, pay attention to the manufacturer’s torque specs during installation. Carbon paste is recommended when installing a carbon bar to reduce the chance of it slipping.
Always use bar plugs or grips with covered ends. An uncapped handlebar can cut you or a fellow rider in a crash.
Don't over-tighten brake and gear levers. They should be snug enough that they don't move during normal use. Any tighter and they might damage the bar, especially in a crash.
After crashing, inspect your handlebar for any visible signs of damage — especially if the brake or gear shifters have been shoved out of place, as surface damage might be the start of a bigger problem. Deep gouges and scrapes in carbon or aluminum are indications that you need to replace your handlebar.