Choosing the Right MTB Handlebar

There are a lot of handlebar options these days. But, choosing the right MTB handlebar is about more than finding a color you like. In this post we’ll help readers better understand what factors go into getting the right bar, the first time.

The two factors that quickly narrow your search are the handlebar clamp diameter and material.

Handlebar Clamp Diameter

Handlebar and stems are available in 35mm as well as 31.8mm diameters. 35mm options tend to be stiffer and, somewhat counter intuitively, lighter. This is because the larger diameter’s additional leverage allows designers to use less material to resist the applied load.

For instance, Renthal publishes their Aluminum Fatbar 35 at 305g while the 31.8mm Fatbar V2 weighs in at 315g.

If you’re spec’ing a new bike or replacing bar and stem both 35mm and 31.8mm are currently relevant. If you’re simply upgrading bars you might shop the diameter you currently have to avoid purchasing a new stem.

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Carbon versus Aluminum Handlebars

Another quick way to narrow down your options is to review material. Most quality manufacturers offer carbon and aluminum options in a handful of sizes.

Without getting into a thesis let’s look at some quick differences between the materials.

Carbon is lighter as it requires less material for similar strengths. Going back to Renthal’s published numbers: Fatbar 35 Aluminum is 305g and the Fatbar Carbon 35 lists at 225g.

If your goal is to build a lighter bike, well, at some point you need to use lighter bits right? So carbon is popular on that front.

Another concept is handlebars sit towards the top of the pendulum of the bike, meaning that weight savings there create a better handling, less “leveraged” by weight. While I wouldn’t want to fill my bars with sand, I will tell you that when you mount a rider on a bike the weight, center of gravity and pendulum all shift notably. I chalk that point up moot.

More than the weight however, is carbon’s additional damping properties.

Carbon Damping

If you’re interested in a research rabbit hole here’s an article about tripods comparing carbon and aluminum, complete with comparison numbers on weight, stiffness and damping. Now, you have to extrapolate it back to our world a bit for bikes but it is a good read. In particular the article notates the SUBSTANTIAL difference between different manufacturers of carbon fiber. One of the reasons you see such a select group of product on BikeCo.com is we know, trust and all would ride any of the brands we sell. Some of the other stuff? Well, nah, I wouldn’t ride it…

OK, so damping. How’s that work? The carbon fiber slightly mellows the spike from the trail into your hands. For instance I have pretty bad hands. If I ride aluminum bars, or the wrong grips, and particularly if I ride both, my hands go numb. Numb to the point that I have to look to see if they’re moving or wait till I feel the grab of the brakes. With carbon bars I don’t suffer from this nearly as much.

In my case the extra $80 to $100 for carbon gets chalked up to necessity. I might look at brakes, saddle, adjustable seatpost, etc as places to find that budget when I’m spec’ing a new bike.

If you are super hard on bars, downhill or free riding, etc – aluminum make a lot of sense from the cost perspective.

You might hear the argument “aluminum bends, carbon breaks”. And under gnarly scenarios that’s true. But the concept that riding a bent aluminum bar is safe is really, really incorrect. That bend has created stress risers and stretched (made the walls thinner) the material. The concept that you’re going to crash in a race, jump up, find the bars bent but climb back on and save what you can from your run? No thanks. A fall that hard ended your race day. Get down safe, collect yourself and ride another day…

So that’s diameter as well as material. Now for the important choices…

Bar Rise

First we’ll look at bar rise. Depending on your physical mobility, how steep of terrain you ride as well as how low of a stack your bike has you’re going to be looking at different bar heights.

Most modern bikes spec a 20mm or 30mm rise bar. Using stem spacers these give you a pretty wide setup range.

You want your bar to be at a comfortable height when climbing without compromising the downhill performance. Too low and the bike will try to “suck under” you in the steeps. This is because the bars aren’t tall enough to put you into a power position to push back as the bike hits terrain features. Too tall and you’ll lose a bit of front end bite on fast, less steep terrain. It’s a bit of a balancing act, but today bikes lean on the taller side for confidence in the gnarlier terrain.

Personally, having some gray hair as well as a back that doesn’t always behave I ride 40mm bars to keep my hands in a position I can pedal the bike. Technically a 30mm bar with an extra 10mm of stem spacer would work, but, I’m a little vane and I don’t like more than a 20-25mm stem spacer stack…

Bar Width

Here we go, rolling into the last and frankly most important section – Handlebar Width.

Overall handlebar width is very personal but the basic concept is this: you need to be in a position that gives you access to your upper body strength while balancing the leverage to counteract the trail.

Super wide bars can feel great in big arching turns. All that leverage means smaller inputs have bigger outputs. Except, when that big rock, or hole or whatever tries to stop the bike in its tracks and send you flying. You need to be in a position of power to “push” the bike through or “pull” the bike over the obstacle. Those super wide bars? Well how many super wide pushups can you do? Less than with your hands more centered under you right?

OK, so not everyone needs monster 820mm bars. So you trim them down to fit. Correct, but, for the best balance of performance you should look at bars that will be just a touch longer than where you plan to end up.

I’m 6’1″ tall and I cut my bars to 780mm, which is probably still a bit wide when I look at Kevin Aiello or Cody Kelley’s setup in the shop. Anyhow.

So knowing that I’m looking to be around 780mm and at 230lbs I want a relatively stiff bar, although with bad hands I don’t want a DH stiff bar were do I look? I’m shopping 800mm, non DH bars for the most part. Narrowing the bars about 2.5% shouldn’t really change the strength (some bars inner profile changes sooner, so there is often a minimum width marking) nor should it change the leverage too much.

That’s the point here. Trimming bars decreases the leverage, which increases the stiffness. Going to 780 from 820 is about a 5% change. Add that the 820mm bars are likely a bit stiffer layup in the first place and the change is more notable than that. Why give up the benefits of your bar’s design, especially for smaller, lighter riders by buying some monster bar and hacking inches off it?

Questions on which bar is right for you? Our team is here to help. We can help you spec the right bar, as well as the right size for your riding.

Finite Details:

What about back sweep and upsweep? Most of the best performing bars come in pretty close here on paper – but on trail may differ slightly.

If you compared brands that BikeCo works with: Enve bars tend to be fairly neutral in handling. RaceFace bars tend to “mellow” or slow a bikes handling just slightly. Renthal bars “accelerate” the handling a tiny bit.

These are all quite relative overall (it’s a small performance window) and all three brands work well. I could comfortably ride any of these bars on my bike without having to relearn everything.

Finally, below are details on BikeCo’s favorite handlebars including width, rise options and disposition.