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Bontrager Race X Lite Aerobars

Written by: Dan Empfield
Date: Mon Jan 23 2012

I assembled Trek's Speed Concept 9-Series tri bike last year. I was prepared for the integrated Bontrager aerobar to be a disappointment—so much so that I made sure I also had in my hand the "steerer stub" that would allow me to bail on the integrated bar, replacing it with the aerobar of my choice.

So I was more than pleasantly surprised to find that the aerobar was not a liability. In fact, it was one of the better aerobar designs that I'd seen over the past year. As I finished the build, made the adjustments, and test rode the bike—and as I rode the bike in subsequent rides—I began to think this much better than any of Bontrager's existing aftermarket aerobars.

I already had used Bontrager's Race XXX Lite Carbon bar, and also the Race X Lite Clip-On. Both were fine. They were good examples of aerobars, so far as they go.

Still, I wondered why a version of the native Speed Concept bar wasn't available aftermarket.

I asked the Bontrager folks about this over the past Autumn and was told, obliquely, that if I was just patient my query might be satisfactorily answered.

Enter the Race X Lite Carbon Aerobar. The very first thing I should say about these bars is that the proper homage to the Wrist Relief extension shape has been paid by Bontrager, and the flat -> descend -> ascend shape works perfectly. This may be the best extension shape currently made. The original Wrist Relief is the only shape that rivals it.
The pads are comfortable. They are on a par with 3T's "Ventus" aka "Comfort" armrests, which have been my favorite.

The bar is extremely adjustable. There is a set of oval pedestal pieces that interlock, and stack on each other like interlocking headset spacers around a steer column. These are made in several heights. Depending on how many of these pedestal units you use, this bar can be adjusted so that the pads are waaaay up in the air. Of course, you know what I'll say: if you need all that height, you've got the wrong bike, or the wrong size, or the wrong fitter. Nevertheless, with this bar you can ride the elevator to the top floor.

These pedestal pieces must be paired with the right set of bolts that pass through the pedestals and terminate into a long female piece, much like the bolt in a front brake caliper that passes through a deep fork crown and into a long female bolt entering from the back of the fork crown. Bolts of several lengths are included in the bar's hardware kit, so that you have all the hardware you need.

If you do need all these pedestal pieces, these plus the bolts end up making the bar somewhat weighty. But that's one price you pay for being way up in the air (the other price is, well, you're way up in the air).
This bar employs a motif that's really become necessary for all new bar designs made these days: The pads and extensions are a fixed system, and the entire system raises or falls in elevation, depending on how high it's pedestaled. This beats the prior method of raising the pads only, because if the pads raise by themselves, you reach out and grab and, lo, there is no aerobar extension there. It's down below. Chapeau to Bontrager for doing this right.

When the pads are affixed to the pursuit bar, you'll note that they're tilt-adjustable. Any pad/extension complex should, on paper, tilt together, and with this bar they do tilt together, rotating downward or upward (so that the hands point slightly down, or tilted up, like Levi likes to ride his aerobars).

Bontrager borrows from companies like Profile Design, who've long been attaching armrests to the extensions, which have in turn been clamped to the pursuit bar. This allows the extension to pass fore and aft—then you cut however much off the rear of the extension that you want—and the pad can sit anywhere along the extension you want it to sit. This is the single most adjustable motif going. But it comes with a risk. Your upper body weight is cantilevered off to the side of the extension. If you don't build the system really well, the armrest clamp will not be able to hold the weight, and you'll find your armrest rotating downward when too much weight is placed on it.
Alternatively, if you make the armrest clamp really well, but the extension is not sufficiently robust, the armrest clamp will just crack and crush the extension when it's tightened too much.

Bontrager seems to have solved both these problems. I really tried to get this system to fail and, so far, with hundreds of miles literally "under" me, no problems.

The aero shape of the pursuit bar is not as deep (fore/aft) as that used in the Speed Concept. However, it does employ the Kamm Tail technology that the bike itself uses in its tube shapes, and this means the lack of a deeper trailing edge does not, according to Bontrager, oblige the payment of a drag penalty.

Cables are internally routed, the exit holes are large, and fishing cables through are actually a bit easier on this pursuit bar than on the one that the version of this bar that comes native on the Speed Concept.

Because this bar fastens to a 31.8mm stem you can rotate it as you wish, while you cannot do the same on the Speed Concept bar (not that this has presented a problem while riding the 9-series SC bikes).
Now let me tell you the potential problems.

The pads, if left unpedestaled, still do sit 6cm above the center of the pursuit bar. So, if you need a low-profile bar (pads that sit lower relative to the pursuit bar), this is not it. There are certainly taller profile bars out there than this one, just, if lowness is a premium for your particular situation, consider that fact when choosing a bar.

One twist on the above: Many Slowtwitchers are aware of the TriRig clamps that replace much of the clamp hardware that attends this aerobar kit. There are two main pluses, for those who need the plusus: There is a 200g or so weight savings on the entire unit; and the base config of the pads is lower by some distance. The pads could mount as low as about 35mm above the pursuit bar, which places them on a par, spatially, with Visiontech's clips.

You do lose some adjustability with the TriRig clamps, chiefly in terms of armrest width adjustment, and the ability to tilt the pads/extensions relative to the pursuit bar. The TriRig clamps cost about $250.
The pursuit extensions—the contact points where your hands hold—sit more forward of the handlebar clamp than is the case with some other pursuit bars (such as the Zipp Vuka). This is user choice. This user would choose a less forward-swoopy bar. I find that this more forward hand position makes for unwieldy steering when I'm out of the saddle. Too slow. Unnatural.

But there is a counter argument. I do find the long steering lever, and forward hand position, better on descents, braking, cornering. So, you give up one thing to get another.

The pursuit bar is 40cm wide on center, though the bar is advertised as a 42cm bar. This width is about average. I'd like to see bar makers skinny that up a little bit in the future, maybe 38cm, maybe 36cm.

The overall rightness of this bar underscores a theme with Bontrager, and you could say the same for Specialized. The "house brand" components these companies make are in many cases equal to those made by well-regarded stand-alone companies. Taking Bontrager as an example, I would use (and do use) its stems, aerobars, road bars, and road tires as readily as I would the products of any brand. Indeed, at this point I consider Bontrager's clincher road race tire collection among the top-5, and maybe the top-3, of all tire brands made.
I hope this is the year that saddles, bars, tires, and other items made by "house brands" reach parity with specialty makers—when warranted—in the minds of the end user. Bontrager is one of those cases, and particularly so with this aerobar.

The Bontrager Race X Lite Aerobar sells for $800. This is a lot money for sure, but, on par for a very good aerobar system that's made of carbon. The bar is not exceptionally lightweight. It's 780g, and that can go higher depending on whether more or fewer pedestal units are used. In contrast, 3T's Brezza II LTD aerobar weighs less than 400g, although with an armrest on part with the Race X Lite's Aerobar pads that's closer to 500g.
The list of really good aerobar systems that are spot-on, right out of the box, is small. With so many of them you have to buy the bar, change out the extensions, or the armrests, to get exactly what you want. This aerobar requires no changes at all. My only wish for the future, for this aerobar, is that there eventually be made a second available pursuit shape for those who want that contact point in a different place; and it would be nice if some of the pedestal hardware were lighter. If there is anything else about this bar worthy of criticism, I couldn't find it.


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