Coefficient Cycling RR Handlebar

Coefficient Cycling's RR handlebar is a drop bar with an aero top, but also some specific ergonomic shaping, and an integrated GPS mount. There's some weight penalty, but it's comfortable, effective and, when well-configured, very easy to live with.

Like it or not, a rider comprises around three-quarters of the system drag of rider and bike, so anything you can do to optimise your position (as well as clothing, helmet, and so on), should benefit your cycling efficiency and save you energy.

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Assuming you already have a good position on your bike, it is usually possible to adopt a more aerodynamic body shape on a conventional drop handlebar. With training, it can be maintained for a reasonable time, but with greater hand and forearm support it's possible to remain aero for longer, which can only be a benefit.

> Why riders like you need to get more aero

At first look, Coefficient Cycling's RR bar challenges what we're used to, but it retains a conventional handlebar's essential positional reference points, and plays around with the bits in between.

The stem clamps to a short round section, which actually aligns perfectly with the bend into the drops, except that instead of joining the two points, the RR bar extends forwards, creating the arrow-shaped loop that supports the integrated GPS mount, while each side of the tops begins from an elevated position, sweeping downwards and rearwards to the drops.

It's this aspect that Coefficient Cycling has patented as 'Swope', meaning sloping, sweeping bar tops. It's claimed to relax your upper body and improve respiratory and neuromuscular function. The slope is 15 degrees, with 12 degrees of back sweep, and the drops have 7 degrees of flare.

The RR bar is constructed from Toray UD carbon fibre and is supplied with your choice of easily swappable GPS mount for Garmin, Wahoo, Lezyne, Polar, Cateye, Bryton, Joule, Hammerhead, Magellan and Mio. The underside of the GPS mounting bridge is also drilled for a proprietary GoPro mount, and I expect a light could be fitted there too, although there's likely to be an adverse effect on aerodynamics.

The 313g weight of our 42cm test handlebar includes the rubber grommets and bungs, a GPS mount, plus a pair of cable guiding tubes on each side.

It's available in 38, 40, 42 and 44cm widths, and the width at the drops is 2cm wider for each size. The flat aero tops are respectively 43mm, 45mm, 47mm and 49mm wide.

Fitting

Fitting is straightforward, with useful graduated markings on the central mounting portion for alignment, and a textured surface which has prevented any sort of slippage with the stem clamp correctly torqued.

I fitted it to a BMC SLR01, with first generation eTap, meaning I only needed to route the brake lines through the bar. The entry holes behind the levers are generously large and well placed for easy access, and using a Park Tool IR 1.2 internal routing kit, guiding the brake lines to the rear-facing exit holes was simple too. There's ample room for gear cables to pass through, and the exit port includes a rubber grommet with two slotted holes to support cables, preventing abrasion and rattling.

This routing aligned perfectly with the BMC's ICS stem, which includes internal routing beneath a cover underneath it, and ensures clean lines.

Deciding on the correct position for the levers was a tougher prospect. My first attempt placed them too low, but a small upward shift created a much more supportive surface from bar to hood, and more relaxed arms and shoulders. The short forward throw from the tops to the drops is angled slightly upwards, which is where I went wrong. Tilting the bar up would have ruined the drop position, and reach to the levers, but my final result felt spot on for me.

Shortly after the bend into the tops, there's a step, which gives you the option to stop taping there, as I did, for a smooth transition into the slightly bulkier tops, or continue further should you prefer.

I chose some 2.5mm thick tape which was, on reflection, a little too thick and stiff to easily wrap around the acute (less than 90-degree) angle after the hoods. It's on, and it works, but something a bit more supple would ease the process.

In use

The position on the hoods is very comfortable and suited to most riding, with great shock and vibration absorption even over extreme washboard surfaces.

I ride in the drops a lot, and set my bikes up accordingly. With an ergonomic compact 127mm drop and 77mm reach, the RR bar felt extremely comfortable when maintaining a tuck for extended periods. Below each lever, a cut-out, stepped section about 25mm high creates a useful place for your thumb to rest, assisting grip, lever reach and comfort, and very slightly decreasing frontal area.

Pedalling on the flat or climbing while gripping the tops showed me the benefit of the Swope design. On long, seated climbs I'm always aware of uneven stresses on my wrists when pulling on a conventional handlebar, but the sloping, backswept design of the RR completely banished that, reducing forearm fatigue and shoulder tension. Even untaped, with track mitts on, the carbon tops proved grippy enough.

One of Coefficient Cycling's headline claims covers the potential for the RR bar to provide a central, extended aero riding position, using the GPS bridge section. According to Coefficient Cycling, the RR bar still complies with the UCI's recently tightened handlebar regulations, and as someone who still owns (but can no longer use) Cinelli's Spinaci Light extensions, this feature was certainly appealing to me.

On the flat, I placed one hand either side of my Garmin, dropped my forearms and shoulders, and pedalled. My road position is quite aggressive – not quite Adam Hansen-esque, but well stretched out, with a 120mm stem and a healthy saddle-to-bar drop – but immediately I needed to angle my elbows outwards to avoid clashing with my knees. My elbows were then in almost the same position as if my hands were cradling the hoods, with horizontal forearms, a position that is far easier to sustain because of the grip on the hoods.

I found I could get lower and decrease the knee clashing by curling one thumb around the base of my Garmin, with the other hand on top, and letting the fingers hold onto the leading edge of the bar. Obviously, I wasn't actually gripping the GPS, but did have a reasonable purchase for control. This was more comfortable, but still far from a TT position, with elbows still splayed out somewhat.

The limiting factor is forearm support, as this position relies on your shoulders and core strength for stability. With practice, it becomes easier, and it's definitely faster than riding in the drops, but lacks the grip and control of having flat arms holding the hoods, and you're further from the brakes of course.

GPS mount

I really like the integrated GPS mount. Compared to even the sturdiest K-Edge mounts, the screen isn't subject to vibration, making it easier to read faster. It should certainly appeal to users of larger devices, which often overwhelm slick but spindly out-front mounts. There's no data on any negative aero effects of a slightly proud GPS unit atop the aero bar tops, but I suspect the practicalities outweigh any extra drag.

Value

The RR costs more than most other aero road bars, but offers something unique as well, which helps justify the extra to an extent. That said, it is cheaper than the Vision Metron Aero which now has an RRP of £429.95.

> Buyer’s Guide: 13 of the best drop handlebars

But Deda Elementi's Vinci does a similar job for £294.99, and weighs 244g, while Pro's PLT Ergo Carbon bar covers the same bases, with great comfort, weighs 230g, and costs 'just' £179.99.

Conclusion

Since fine-tuning my position on the RR bar, it's become a favourite because of its impressive comfort and enhanced hand positions. I tortured myself in some fairly contorted positions throughout years of time trialling in the 80s and 90s, and these days I welcome improvements that do legitimately increase my physical comfort on the bike, as I know it'll pay me back in the long term.

Although expensive and a little weightier than most, and not the huge game-changer I was hoping for, the Coefficient Cycling RR has no real disadvantages when compared with other aero road bars, but does offer some uniquely useful positives.

Verdict

Ergonomic, go-faster aero bar with unique looks and some tangible benefits