By Tom Demerly.
Different shape, different material: Different ride quality. It’s a simple equation that works wonderfully on the Cervelo R3. The recently and consistently refined Cervelo R3 is a well engineered blend of comfort combined with performance oriented stiffness- attributable to a number of unique engineering innovations. They are all worthy of consideration if you are shopping for a high end road bike. The R3 is a bike that belongs on every high end road bike shopper’s short list. As you consider the R3 compared to other road bike offerings the Cervelo exclusive engineering features keep bumping it up the list. For me, the R3 sits at the top of that list.
The Cervelo R3 is Cervelo’s predominant “stiffness and comfort” bike. It is a bike with design features that add bottom bracket stiffness while providing an uncanny degree of comfort. The R3, like all Cervelo designs, is an evolution of previous Cervelo models. And like other Cervelo designs, it has proven itself over and over in the competitive arena.
R3 began in any number of Cervelo designs that include test bikes rigged with strain gauges to measure the effects of frame deflection under pedal load in the real world. The shapes and materials evolved as the engineering problem became more defined: Build a stiff bike at the bottom bracket that was comfortable to ride. Since the R3’s introduction the evolution has not stopped, with the recent inclusion of the BBright bottom bracket, improvements in materials and carbon lay-up and additional bike models such as the RS with an evolutionary branch growing off the tree of the R3 family tree.
There are two Cervelo road bike groups: The Squoval or Stiffness to Weight Ratio road bikes such as the R3, R5, RS and exotic and rare R5ca (California Project) and the aerodynamic road bikes, the S3 and S2.
The goal of the Squoval or “Square-Oval” bikes is to improve performance through additional stiffness and comfort. The two agendas seem in conflict. That accounts for so many unusual frame features on the R3. Some of the unique features of the R3 frame are visually striking such as the girder-like down tube and gossamer seat stays as viewed from the side. Other features are invisible, such as the interior cross section of the squoval down tube, with its complex wall shapes. Another recent innovation in the R3 is the addition of the BBright system that Cervelo says almost doubles bottom bracket stiffness.
The Frame Features:
Squoval Down Tube.
Squoval is the name Cervelo uses to describe the unique shape of their down tube on the R3. It is a combination of “square” and “oval”. The shape is complex, with a series of curves on the outside of the frame terminating in four tight radius corners to form what appears to be a square-ish down tube. The inside of the Squoval down tube is shaped differently, with a rounder cross section internally. Cervelo calls this “Smartwall for Carbon”. The result is material distributed to the areas needed to resist torsional stress and material reduced in the areas where it isn’t needed to save weight.
The Squoval down tube makes the R3 feel more solid not only on climbs and accelerations, it stiffens the chassis of the bike, improving steering, braking and acceleration and drivetrain performance.
I’ve ridden the earliest versions of Cervelo’s road bikes going back to and before the R2.5. The ride quality is easily distinguishable between the R2.5 and the R3. I likened the R2.5 to a Colnago C40 in terms of road feel and stiffness: A luxurious bike that could have been stiffer at the bottom bracket. R3 improved stiffness and retained comfort with better construction techniques, different seat stays and the Squoval down tube. Squoval works: It improves stiffness and ride quality compared to non-Squoval bikes.
BBright is Cervelo’s proprietary design that picks up where Squoval drops off. BBright orients stiffness to the non-drive side of the frame, the side that has been more flexible on symmetrically configured, conventional road frames. When you view a BBright bottom bracket, down tube and seat tube at the bottom bracket area it is offset to the mounted rider’s left. Additionally, the left chainstay is wider than the right chainstay by a substantial margin. BBright also uses a 30mm axle for additional stiffness. Cervelo suggests the BBright configuration almost doubles bottom bracket stiffness.
The R3 was previously available in a version called the “R3SL”, a bike made famous in the Tour de France for its rule-busting light weight and enhanced stiffness, especially in the mountains. The R3SL has evolved, effectively toward a new bike called the R4. The new BBright adds similar stiffness improvements to the bottom bracket of the R3 as you’d experience on the R3SL, albeit at slightly higher frame weight but much lower price.
BBright may be the single greatest upgrade to the R3 frameset other than the evolution of the head tube.
Optimized Head Tube Taper: New 1&1/8” to 1&3/8” Head Tube.
Cervelo engineers deserve recognition for not accepting the norm. There has been a tireless effort to move toward improvement. Their new head tube configuration is another example of the evolution. The newest version of the R3 uses a conventional size 1&1/8” top bearing but goes to an innovative 1&3/8” lower bearing. The concept of wider bearings on the bottom of a headset along with the attendant increase in head tube width is not new. What is new is the recognition that it isn’t as simple as “if wide is good, wider is even better”. Cervelo tested wider and narrower head tube bearing combinations and their interaction with weight, stiffness, ride quality and even steering. They landed at an elegant convergence of efficiencies between these agendas at 1&3/8” for the bottom bearing. This design works in synergy with the Squoval down tube, which is turn works with BBright to enhance ride quality, stiffness and performance. The result, combined with ongoing improvements in layup and internal configurations is a substantially improved version of the R3 for 2011. Each performance feature compliments the next.
Ultra Thin Seat Stays.
I remember the first time I saw an early R3. I could not believe the seat stays. They looked like leaf springs. Phil White, one of Cervelo’s engineers and founders, said “Good observation”.
The seat stays on the R3 are extremely thin as viewed from the side, but quite wide as seen from the top. The stays work together with the seat tube and its exotic taper and the massive chain stays. Some of these engineering themes aren’t entirely new, but Cervelo has optimized them in design and with materials. Ben Serotta employed similar ideas to a lesser degree in early Serotta Colorado bikes used by top pro teams under sponsored brand names. In simplest terms, the seat stays are vertically compliant but laterally stiff. They help moderate road shock as transmitted from the rear wheel. Cervelo has learned and confirmed that most of our “feeling” of the road comes from tire, wheel and air pressure variables. That said the Ultra-thin seat stays exert an influence on how you feel the road, moderating road shock while maintaining stiffness. It’s difficult to pick one feature I like best on the R3, but the seat stays would tie with the Squoval down tube. When I think of the R3 I think firstly of Squoval down tubes and gossamer seat stays.
The Mechanical Details: Reverse Seat Tube Binder Collar and Single Bend Cable Routing.
The R3 has an abundance of conspicuous engineering features like BBright, Squoval down tube and Ultra-thin seat stays, but two subtle mechanical details are equally impressive and functional.
The reverse seat collar design puts the seatpost binder bolt in front of the seatpost, not behind it. The logic is inescapable. Load is concentrated by the weight of the rider at the back of the seatpost. When the seam or opening of the binder collar is at the back it takes most of the load. Therefore, the collar has to have significant material added to it for strength. The most elegant solution is to move the fastener- the binder bolt- to the front of the seat tube, where load is reduced. The weight of the collar can be reduced to only 8 grams. The design is “key-way” with a flat surface on the rear so assembling it incorrectly or having the clamp twist on the seat tube of the frame is impossible. It’s an elegant engineering solution that saves weight and increases strength.
The Single Bend cable routing reduces the amount of corners your drivetrain cables have to make between the shifter and the derailleurs. This improves shifting performance by reducing friction on the cables. This cable routing makes the drive train feel more responsive and adjust more easily. It is another elegant, refined approach to a basic design challenge.
Component Spec and Build Kits.
Cervelo depicts four different build recommendations on their website for the R3, ranging from a $3200 SRAM Rival kit with Fulcrum wheels to a $5500 Dura-Ace equipped version. The build kits generally suggest 3T bars and stems, Fizik Arione saddles (one of my two favorites along with the Cobb Cycling SHC 170) and a variety of nice cranks that may include the ROTOR 3D+ on the SRAM Red, Dura-Ace and Ultegra bikes. Each of the build kit recommendations is excellent, I especially like the cockpit, saddle and wheel spec. If I made one change across the spec chart recommendations it would be on tires since I’m a Continental fan.
“If I could have any road bike in the industry as my personal bike, the R3 would be my choice.”
There are epic rides in Tucson: Mt. Lemmon. The Shootout. Gates Pass. The environment in the Winter Training Capital includes pavement that ranges from pristine to pave’ and terrain that goes from board flat to undulating to one of the longest sustained, paved climbs in the US. In Tucson you need a stiff bike for climbing and descending that can hold up on any pavement and provide nice ride quality. R3 is a perfect Tucson bike- at home on the shoulders of Mt. Lemmon and well mannered on the sun-baked desert pave’ south of town. I particularly like how the R3 unloads off a climb like Mt. Lemmon, with a feeling of safety, stability and predictability missing from a lot of lightweight carbon bikes.
If I had a pick of one bike from the Cervelo line it would be the R3. As a matter of fact- If I could have any road bike in the industry as my personal bike, the R3 would be my choice. It is well refined convergence of optimal engineering features that produce a banquet of tangible benefits. No other bike from any manufacturer includes the engineering features of the R3.