Bontrager XXX Aero Handlebar

The XXX Aero bar sits in Bontrager's top range of kit and components. With a full carbon fire construction, internal cable routing and some aero flattened top sections, it's designed for riders who want ultimate stiffness and wind-cheating performance. While it might achieve both those things, it's a pain in the proverbial to get there...

When you ride the XXX, that stiffness really stands out; apart from a tiny amount of flex at the drops under massive load, such as when you're sprinting, it doesn't move a millimetre. And that bit of flex at the extremities means it isn't uncomfortable riding in the hoods on long and steady rides as it takes the sting out of any vibration coming through from the road.

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For those efforts where you're tapping out a rhythm on a climb, for instance, using the top section, it feels really solid. The flat sections also give a nice platform to rest your hands on, great for those really long climbs.

Like most bars these days, the Bontrager is a compact design. That means a much shallower drop than more traditional curved or anatomic bars that were prevalent 10 or so years ago.

With a distance of just 125mm from the aero section to the top of the dropped part of the bar, the XXX offers more accessible hand positions for many riders – you can get into a more aero tuck without having to crouch really low, ideal for those with poor flexibility.

Bontrager also flares the drops out at the bottom width-wise, which gives you extra wrist clearance when in a sprinting position. On the subject of width, it's worth noting that Bontrager measures its bars centre to centre rather than outside to outside, so this 42cm bar is actually 44cm in total.

The centre section is 31.8mm diameter, like most oversized bars, and it's good to see that the round profile extends far enough either side of the stem to let you fit accessories such as out-front Garmin mounts or lights, for instance.

So, as far as comfort, stiffness and riding position goes, everything is pretty rosy – but there is a fly in the ointment.

There's nothing wrong with internal cable routing, but here, to be honest, it's just too tight. The cables enter through two holes just behind where the hoods of your shifters sit, the one on the inner face of the bar having a groove to run the entering cable into the hole. The cable outer will then run through the bar, exiting out of the rear slots either side of the stem clamp area.

Getting the cables threaded through the bar from the shifters is a time-consuming process and a real pain. The slots and holes are just too restrictive, which means when you finally get the cables through, the outers' casing is scratched to pieces.

With no room to move, the cable run is also tight through the bar, which means gear shifting and braking is compromised. The brakes feel a little squidgy at the lever because of the friction of the inner cable against the tight bend of the outer, with the gear changes also feeling less crisp. It reminded me of the tortuous cable runs and performance found on my previous time trial bikes – not what you want on a sharp-handling race machine, which is where'd be likely to fit this Bontrager bar.

Replacing this XXX with the internally routed ITM X-One I tested, and both shifting and braking returned to their previous levels.

Another thing to consider when you're thinking about buying the XXX is value – or rather, lack of. Carbon bars aren't cheap, and for good reason. They've got one hell of a responsibility, supporting a rider's weight through potholes, climbing forces and braking loads while being as light as possible.

> Read more road.cc reviews of handlebars here

Aero bars will never be especially light because they require more material than a round bar, but at 220g the XXX is pretty much spot on against other carbon bars we've tested. But to put that weight into perspective, this is 125g lighter than the alloy Bontrager version we tested a few months back; to save that much weight, your wallet gets lighter to the tune of £180. Value? That's a decision only you can make.

In conclusion then, the Bontrager is very pleasant in use, offering loads of stiffness but with just enough give to keep the comfort levels acceptable. The shape of the drops is good, too, with the shallowness and short 85mm reach making them ideal for those who don't like to contort themselves into a ball to get aero.

That cable routing, though... It's a massive obstruction for even the most competent of DIY mechanics; maybe in the hands of a professional things are better, but if I'd just laid out this amount of money on a new bar I wouldn't want to spend three hours threading cables, to still find that shifting and braking were compromised.

Verdict

Comfortable, lightweight bar but a pain to set up, with cable routing compromises that shouldn't have to made at this price