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Verdict: 
Comfortable, lightweight bar but a pain to set up, with cable routing compromises that shouldn't have to made at this price
Weight: 
220g
Bontrager XXX Aero Handlebar
6 10

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.

Bontrager XXX Aero - detail.jpg

Bontrager XXX Aero - detail.jpg

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.

Bontrager XXX Aero - detail 2.jpg

Bontrager XXX Aero - detail 2.jpg

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.

Bontrager XXX Aero - detail 3.jpg

Bontrager XXX Aero - detail 3.jpg

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

road.cc test report

Make and model: Bontrager XXX Aero

Size tested: 42cm, 31.8mm clamp

Tell us what the product is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?

The XXX Aero is an aerodynamic version of Bontrager's top end carbon fibre bar. It's a match of low weight and wind cheating profiles, at a premium price.

Tell us some more about the technical aspects of the product?

From Trek's website:

KVF profile top section saves 23 seconds per hour compared to traditional round bars

Internal cable routing for Di2 and standard housing

Laser-etched brake lever position lines for spot-on control setup

UCI-Compliant

Unconditional Bontrager Guarantee

Bend : VR-CF

Drop : 125mm

Clamp Size : 31.8mm

Reach : 85mm

Color : Matte Uni-Directional Carbon

Rate the product for quality of construction:
 
8/10

All the edges are very smooth and well finished, plus you can hear the change in wall thickness when you tap the centre bulge revealing that there is more material there.

Rate the product for performance:
 
6/10

Without the cable routing issues this bar would easily score 8 here, as it is very good indeed on the bike – comfortable and stiff without being harsh. The internal cable routing is poor, though, and if I'd just laid out 250 smackers on new bar I'd be truly disappointed.

Rate the product for durability:
 
7/10

Always a tough one for carbon components as one whack can seriously weaken a product. Crash damage aside, the XXX doesn't creak or flex in any way that would make you worry.

Rate the product for weight (if applicable)
 
9/10

220g is pretty impressive for an aero bar.

Rate the product for comfort (if applicable)
 
8/10

The flat top sections offer a good platform for long rides.

Rate the product for value:
 
4/10

Expensive, even for carbon aero bars.

Tell us how the product performed overall when used for its designed purpose

Stiff bar with a nice shape, great for when you're out for a quick blast.

Tell us what you particularly liked about the product

The quality of the finish.

Tell us what you particularly disliked about the product

The cable routing.

Did you enjoy using the product? Riding it – yes; fitting it – no.

Would you consider buying the product? No, too expensive.

Would you recommend the product to a friend? Only if they were using electronic gears – it's much easier to fit wires through the holes than cables.

Use this box to explain your score

If I bought a bike with this bar already fitted I'd be happy. To ride on it is a joy. It offers a nice fit for your hands, the shallow drop is great, and it has just enough give to make sure things aren't harsh. If you've got to fit it yourself, though, it's an absolute pain in the backside. The cable routing holes are way too small, with the bends in the cable very tight which affects shifting. At this price there should really be no compromises to make.

Overall rating: 6/10

About the tester

Age: 37  Height: 180cm  Weight: 76kg

I usually ride: This month's test bike  My best bike is: Mason Definition

I've been riding for: 10-20 years  I ride: Every day  I would class myself as: Expert

I regularly do the following types of riding: time trialling, commuting, club rides, sportives, fixed/singlespeed

Stu knocked out his first road.cc review back in 2009 and since then he's chucked the best part of seventy test bikes around the West Country, a couple of them quite literally! With three alloy and two steel bikes in his fleet he's definitely a metal man (that'll be the engineering background) but is slowly warming to that modern carbon fibre stuff along with fat tyres & disc brakes.
It's not all nostalgia though, after spending the last few years in product design Stu keeps banging on about how 3D printing is going to be the next big thing and he's a sucker for a beautiful paint job too.

1 comments

Avatar
guyrwood [894 posts] 12 months ago
0 likes

I'm filing these under 'Bike porn but unjustifiably expensive'...