Simple integration and a dramatic new tube shape mark QR’s latest flagship.
Quintana Roo, the creator of the first widely produced triathlon bike, revealed a new top-tier tri bike days before Ironman 70.3 California. It is of course designed to maximize aero performance and fit, but has a special emphasis on usability and function. QR has the deepest history with the sport of all the bike makers and the PR Six reflects their awareness of the needs of triathletes, which stretches beyond speed in a wind tunnel.
Frame structure is one of the most obvious changes from Quintana Roo’s prior flagship bike, the Illicito, to this one. The Illicito didn’t have a non-drive-side seat stay, which reduced drag in some conditions according to Quintana Roo. It also significantly compromised stiffness. I was able to get the rear tire to rub the frame when sprinting and it also flexed dramatically when mounted to a trainer. The PR6 reverts back to the classical double-diamond frame shape, with all tubes present and accounted for.
For the first time in its history, Quintana Roo is using a fork with a fairing over the head tube and proprietary stem system, placing this bike in the always intriguing “superbike” category. Testing conducted by other frame manufacturers and shared with Triathlete has found that a similar front-end system on another top-level bike saves a very modest amount of drag. Adding another vertical tube to the front of the bike buttresses the frame and can improve lateral stiffness and change the perceived ride characteristics of a bike.
Sitting on top of the fork is one of the most simple and user-friendly proprietary integrated stem systems. It features a reasonably wide range of adjustment in most dimensions and one weakness in terms of fit adjustability.
Quintana Roo’s proprietary low-profile stem mounts directly on top of the upper headset bearing and juts forward off the frame. It is drilled in three places to create three affectively different stem lengths, offering two centimeters of fore-aft adjustability. Once installed, this piece never needs to be removed. By leaving this piece in place when traveling or adjusting bar height, QR has completely eliminated one of the most common mechanical difficulties triathletes experience—a loose headset. Mounting a stem to a bike with a typical stem-and-steerer tube front-end assembly may seem intuitive to experienced mechanics, but it’s the source of a great many problems for triathletes. There is a specific order in which the bolts must be tightened to correctly engage the headset bearings. Do it in the incorrect order and the front end will rattle. Ride a loose front end long enough and the head tube will be damaged.
Mounted on top of this stem is a modular system that attaches the base bar. The base bar clamp can either bolt directly onto the stem, or it can be raised to increase fit stack height. QR includes three 5mm spacers to elevate the base bar. This system is incredibly easy to assemble, making quick adjustments a breeze and completely realistic for the at-home tinkerer. Three bolts pass through the base bar clamp and through the risers before threading into the stem. Check the photo gallery for pictures—the system is easy to understand when you see it.
When the base bar clamp is mounted directly to the stem, the base bar’s effective height is 5mm lower than if it were to be mounted to a negative-17-degree, 100mm-long stem. This is a really low orientation. The frame’s sensible fit specs (details below) help make this position a little more attainable, but it is still relatively demanding. With all three risers mounted below the base bar, the brake grip position comes up a bit, but it is still not a particularly forgiving position. The PR Six relies on the aerobar to make any necessary dramatic adjustments to fit reach and stack. Profile Design’s Aeria bar, included on this model, is up to the task. It can elevate the extensions dramatically and shorten or lengthen reach to both the pads and extensions. Because of the smart bar spec, aero position fit stack can come up dramatically. But the base bar is stuck in a lower position—this is the system’s one fit limitation. Quintana Roo could overcome this problem by creating stems with a taller stack height.
Creating a bike that is both functional and livable was one of Quintana Roo’s major objectives with this bike—brake selection is one of the most obvious examples of this philosophy. The front brake recommended for this bike is a direct-mount Shimano Ultegra caliper. Two bosses located at the wide points of the fork blades are the attachment points for this powerful and practical caliper. While many other tri bikes compromise stopping performance to shave a few grams of drag by employing a hidden brake and hiding the housing in the frame, Quintana Roo went the other direction. This design creates a small but measurable amount of additional aero drag and is extremely easy to maintain and travel with, plus offers outstanding brake force modulation and feel.
One of the biggest differences between a triathlon bike and a time trial bike is frequency of use. A triathlon bike is its owner’s primary training bike and typically gets the most use, while a TT bike is rarely ridden. To make up for the fact that triathlon bikes get a ton of miles before race day and are often doused in sports drink, going with a direct-mount Ultegra caliper makes a triathlon bike more practically functional than practically all other options. If you’re married to a single brake-bolt system, the PR Six also has a brake bolt in the center of the fork. The rear brake, hidden under the bottom bracket, also takes a direct-mount Shimano brake caliper with the option to use a more typical brake.
Quintana Roo has come up with their own variation on the truncated airfoil concept that Trek first popularized for bikes with Kammtail-shaped tubes on the Speed Concept. Lopping off the back of an airfoil, the thinking goes, allows a tube to behave as if it was a deeper, fully formed airfoil when moving at bicycle speeds and wind angles. Tube shapes of this variety often have a flat surface at the rear of the tube, which intuitively looks to be a likely place for a drag-inducing low pressure air pocket to form. In reality, truncated airfoils have been shown to be very fast over a wide variety of angles and conditions. Quintana Roo’s version of this concept is called Boat Tail. The tubes are shaped similarly to a triangle with the pointy end facing forward. Unlike Trek’s Kammtail tubes, the broadest point of the PR’s down tube is very close to its trailing edge. Boat Tail is also used on the seat tube and seat stays.
Quintana Roo went with this unusually shape for the PR’s down tube in part to help the bike perform well with a round bottle mounted to the frame. Quintana Roo states that adding a round bottle to the frame increased drag in a test by 38 grams at 30mph, which is a bit less of a penalty than typical round-bottle drag numbers.
Bottle bosses on the seat tube, down tube and on the top tube (not present on the pre-production model photographed for this article) are the only storage options included with the bike. QR advocates for external systems made by companies specializing in accessories.
The down tube is situated to minimize the gap to both the fork crown and the front wheel. It juts forward from the bottom bracket by different distances based on frame size before rising to meet the head tube. This small adjustment allows the bike’s aero characteristics to stay relatively consistent across all sizes, states QR, preventing the gap from growing or shrinking based on the frame size.
Amazingly, the only tools needed to assemble and disassemble this bike for travel (when built with Profile Design Aeria bars) are a 4mm and a 5mm Allen wrench. With these two simple tools, the front end can be disassembled and the rear derailleur and seat post can both be removed. Eliminating other fasteners helps make maintenance and travel that much easier.
Quintana Roo has always been at the front of trends in seat tube angle. Back when most bikes used 76-degree tubes, QR was at 78. When the rest of the bike makers caught up and went to 78, QR was already able to hit 81 degrees. Their newest creation goes even steeper. The true seat tube angle is 80 degrees and the saddle clamp can be moved forward to an effective 83-degree position.
Rear dropouts are replaceable and reversible. The PR can be set with vertical or adjustable horizontal dropouts to fine-tune wheel position.
The frame uses a Pressfit 30 bottom bracket.
Here are the stack and reach data for the PR. QR cleverly decided to same the frame sizes after their stack height. These sizes follow the trend toward less aggressive frame geometry.
Size 46: Stack 46, Reach 37 (650C wheels)
Size 50: Stack 50, Reach 39
Size 52: Stack 52, Reach 41
Size 54: Stack 54, Reach 42.5
Size 56: Stack 56, Reach 43.5
Size 58.5: Stack 58.5, Reach, 44.5
Not to be overlooked, the smallest frame size is built with 650C wheels. These smaller wheels are the most appropriate fit for bikes of this size because their scale is more proportional to the rest of the frame.
Size availability of the bike will fill out gradually over the next few months. The size 52 will be available in about three weeks and the new sizes will trickle in slowly until all six sizes are in the US. 50 will be next, followed by 54. The frameset is priced at $4,500 and the complete bike (without the Reynolds Aero 72 wheels shown in the picture) will be $8,500. Quintana Roo is continuing to lead the way for tri bike manufacturers by stocking cranks with shorter than average arms.