Quintana Roo PRSix triathlon bike review

With a novel approach to stem design and tube profiles, does the PRSix set a new personal record for Quintana Roo?

Our rating 
4.5 out of 5 star rating 4.5
£3,400
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Quintana Roo PRSix triathlon bike review

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It takes five screws and a lot of patience to set up the PRSix’s cockpit. Not because it’s fiddly but because no matter how good your position, you always feel you could improve it. It’s a testament to how accommodating the bike’s front-end is and the deceptively simple-looking but high performing stem.

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Rather than the traditional ‘tube-with-a-clamp-at-either-end’ stem, the PRSix uses a platform on to which you bolt the required number of plates to raise the top-loading bar cradle to your preferred height. It’s a bit like one of those 3D sculpture puzzles, but it’s so quick and easy to ‘solve’ that it almost torments you into trying different configurations, just in case the next one’s that little bit better.

But the stem isn’t the only thing that marks the PRSix out from the rest of the Quintana Roo range. It also benefits from a fork with a prow that sits in front of the head tube, ‘boat-tail’ tube profiles, a down tube that draws air away from the drivetrain and an enormous non-driveside chainstay, which has been shaped so it eliminates its leading edge.

Brad DeVaney, head of product design and development for Quintana Roo, is the man behind the PRSix and says sizing is the key to the bike’s performance – not only in terms of rider position but also aerodynamically. “The PRSix allows the most contemporary positioning in very broad windows of fit,” he says, “and we’ve got a nice overlap in position capability in each [frame] size… We can find your position probably on two, sometimes three, sizes.”

But perhaps more importantly, the PRSix’s aero benefits are virtually uniform across the range so you get the same advantage no matter what size you feel most at home riding.

“The angle of down tube typically changes across a bike’s size range. That’s not the case with the PRSix; it’s a fixed angle,” says DeVaney. “What I grew frustrated with – not just with our bikes but our competitors’ bikes too – is the variation in performance along the size range. The differences came down to these subtle geometric changes that would affect the air behaviour off a given front wheel.

“If I’ve got a front wheel that opens and closes the air very effectively, a different down tube angle or position is going to give a different [aero] characteristic. So I created a common [element] in the entire PRSix size range: the down tube. Every PRSix performs nearly identically, depending on the height of the [seatpost].”

A smoother path to follow

The down tube is at the heart of the PRSix’s design and it does some interesting things as it reaches the bottom bracket shell. It becomes asymmetrical and bulges out more towards the non-driveside. The idea behind it is to draw airflow away from the chainset and towards the smoother path along the oversized non-driveside chainstay.

The down tube is asymmetrical at the bottom bracket shell to draw airflow away from the chainstay

Aside from its elephantine chainstay, the other most noticeable thing about the frame is the tube profiles. They’re neither the full-length teardrop nor the truncated, flat-back Kamm tail. Instead, the tubes use what’s known as a ‘boat-tail’ profile, which is truncated but also tapers slightly before ending with a flat but narrower back.

It allows the PRSix frame to sit in a sweetspot where weight is kept low but stiffness can remain high without compromising on aerodynamic efficiency or stability in crosswinds.

Dura-Ace bar-end shifters are complemented by Profile Design’s aluminium Aeria aerobars

A Shimano Ultegra groupset is complemented by Dura-Ace bar-end shifters and brake levers, and a FSA crankset and bottom bracket. Your arms rest on Profile Design’s aluminium Aeria aerobars while your backside is supported by an ISM Adamo Time Trial saddle. The wheels are Shimano’s solid, if unspectacular, RS-11 hoops dressed with Continental Grand Sport Race rubber.

Whistling while you work

The PRSix rides superbly when you’re on the aerobars. Even though you’re almost entirely tucked over, it feels natural and stable. It’s amazingly responsive, too – you can flick it around unexpected potholes without thinking, let alone having to jump back onto the bullhorns.

That responsiveness is partly thanks to the frame’s stiffness but also how light it is. Granted, 8.5kg may seem average for a top-of-the-range bike (considering the Specialized Shiv Elite weighs the same and costs nearly £1,000 less). But when you consider that the wheels alone weigh 2.5kg, you begin to appreciate how light the PRSix chassis really is.

So why have Quintana Roo specced these heavy, low-end wheels? Well, partly because they expect most people in the market for the PRSix to have very specific preferences regarding what race wheels they require, and also because it takes some sting out of the price tag.

But even with the relatively mundane RS-11 wheels, the PRSix manages to accelerate instantly and easily. Were you to sling in a lighter, more aero pair of hoops it really would take off like a rocket.

Aside from the wheels it comes with, is there anything not to like about the PRSix? The vertical geometry and wide, stub-nosed ISM perch mean getting out of the saddle isn’t too easy, primarily because the saddle can get in the way of your thighs. But you can minimise that by adjusting the effective seat angle, and, more to the point, the PRSix isn’t intended for out-of-the-saddle climbing or sprinting.

Despite an unwelcome whistling noise coming from the top tube, we found the PRSix to be an ‘amazingly responsive’ ride

The only other niggle is that it whistles. It sounds like someone playing a recorder when you’re just riding along but turn into a headwind and you’re treated to an impression of Anchorman’s Ron Burgundy warming-up for a flute solo. The noise comes from the top tube but, despite taping over the bento box mounts, there doesn’t seem to be any way to silence the soundtrack. Even with the freestyle background music, however, we found the PRSix to be a seriously classy ride.

Verdict: A near-endless potential for fine-tuning position, and a spectacular ride when you’ve made your mind up! 92%

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Contact : www.quintanarootri.com