The range of handlebar choices is therefore now vast, from sub-100g racing exotica, to burly downhill racing bars designed to stand being nuked from orbit.
Here's what to look for in a mountain bike handlebar.
More width gives you more control, but slows down your ability to snap the bike into turns. Low, narrow bars make you more aerodynamic and ergonomically efficient for long stretches of pedaling. Cross-country racers therefore favour bars in the 22-23in (56-58cm) range, while freeriders and downhillers go wider.
The general consensus is that the most efficient compromise between comfort, control, leverage and confidence is 4-6in (10-15cm) wider than your shoulders. Some riders might prefer more width for more leverage, some might prefer less because their wrists or shoulders hurt on wider bars. Try a few and pick your favourite.
There's a case for always buying a bar that's slightly wider than you think you'll need because you can cut it down. However, see the comments below on trimming bars, and if you go this way, make sure that there's room for the controls at the narrowest you're likely to choose. The centre section of some riders bars limits the inwards movement of the brake lever and shifter mounts.
Materials and design
Most mountain bike handlebars are made from aluminium alloy of one sort or another. Steel is also used when ultimate strength and durability is required, while carbon fiber is gaining popularity at the high end. A handful of manufacturers still offer titanium bars.
As in frames, you can't say which material is 'best' because design and manufacturing makes more difference to the strength and durability of a bar. However, 6000 series aluminium will make for a heavier bar than 2000 or 7000 series because it's less strong. If weight is important to you, look for the stronger alloys.
Alloy bars can also be internally and externally shaped (butted) to give specific strength and stiffness at different points in the bar to cope with various loads and leverages. Some are also surface treated (anodised or shot peened - bombarded with small balls) to eliminate weak spots caused by surface irregularities.
It's often very hard to tell how consistent the manufacturing quality of the bar is under the surface though, unless the manufacturer stress tests and certifies each bar they make. Price pressure means that only a few brands do this though, and it does seem that most manufacturers have learned the lesson of the super-light bars of the early 90s, some of which were scarily fragile.
If you want the ultimate in fail-safe strength though, go for steel. It's heavy and stiff, but even if you do land hard enough to crush them, steel bars tend to droop and fold gently rather than snapping suddenly.
Rise and sweep
Handlebar shape, often referred to as up-sweep or rise and back-sweep, are as crucial to comfort and performance as width as not everyone's arms, wrists and comfort zones are the same. Some riders feel better with a swept-back bar and a higher position.
Others might prefer a lower, narrower, straighter-bar setup. The right rise also depends on fork height, frame head tube length and stem height. The back-sweep of a bar may be the most important factor.
Most bars now come in a choice of two different clamp diameters - traditional 25.4mm (one inch) or oversize 31.8mm. Increasing the diameter of the bar center increases its stiffness and strength for only a small increase in weight, and the same applies to oversize stems. This is, theoretically, a very good thing for all but the most fevered weight watchers. We wouldn't recommend changing your bar and stem just to switch from one size to another, but if you find yourself replacing both at the same time, then you have a choice.
Trim the rim
If you like the shape and style of a bar but it's a bit too wide, you'll usually be able to trim the ends. Read the manufacturer's instructions first, though, as some will say that cutting the ends will void the warranty. If you want to trim a bar, use either a pipe cutter or a hacksaw. Pipe cutters can make a mess of very thin-walled bars by crushing them, so careful work with a very fine-toothed hacksaw is better. Make three cuts around the bar so you're never sawing right across the wall, and tidy things up with a file. An old grip clamp makes a handy saw guide.
Plenty of riders are still using bar ends, and with good reason. They might not be fashionable, but they provide a welcome change of hand position that can provide good leverage on climbs and a comfy cruise posture on long, flat sections. If you like them (yes, even on risers) then use them.
We particularly like the Ergos, from Cane Creek, Stubbys from X-Lite and Ergon grips that incorporate bar ends, but there are loads of others to choose from.
Tips and tricks
Always use bar end plugs or grips that cover the ends. An uncapped handlebar end can take a nasty cut out of your body in a crash. Make sure that your stem is well suited to your bar - same brands are often a good idea. It's crucial that the stem clamps perfectly on to the surface of your bar. If it doesn't, it might damage the surface and set up a point of stress that could cause a breakage at a later date. If you want to fit bar ends on a superlight bar, read the manufacturer's warranty details to make sure the ends are strong enough to support bar ends. We've seen bars that exclude the use of bar ends from warranties.
- Don't over-tighten brake and gear levers - they should be snug enough that they don't move. Any tighter and they might damage the bar, especially in a crash.
- After crashing, look for damage on your bars - especially if the brake or gear shifters have been shoved out of place - as surface damage might be the start of a bigger problem later. Most manufacturers will recommend that you replace your bars and stem after an obvious impact.
- Experiment with bar 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.