One of the lightest road bikes in the world!
The R5 frameset is be the production version of the RCA version, and will share Squoval 3 shapes to
improve aerodynamics and stiffness. The R5 brings Cervelo's RCA engineering into the regular line-
up. With the new Squoval 3 TM tube shapes, aero meets ultimate lightweight design. Sure-footed riding is assured with clearance for 700x25c tires. Climbing and cutting through the wind with ease are matched with excellent stability and control.
The R5 builds on the proven Squoval3-profile tubes, big chain stays, and tiny seat stays but it's as if Cervélo turned the volume up a few notches. Key changes including a tapered front end and interesting BBright bottom bracket standard with a 79 mm wide BB shell.
Cervélo says that in-house testing revealed definite advantages with a tapered front end but that the commonly accepted 1-1/8" to 1-1/2" standard was actually too rigid. Cervélo ultimately settled on a 'sweet spot' of 1 3/8", using a lower headset standard. The perfectly matched to the frame properties fork is still light but noticeably stiffer with more precise handling. In addition, the lower bearing seat is molded directly into the fork crown, thus eliminating a redundant part and also lending a straighter path for the carbon fibers in that area.
The new Squoval 3 tubes are stiff, light, and now aero, too. Squoval adds enhanced aerodynamics to Cervelos second-generation Squoval tube shapes by sculpting the leading edge and tweaking the trailing edge. With a savings of 7.4 watts compared to second-generation Squoval, Cervelos new Squoval 3 means you no longer have to choose between optimal lightweight engineering and aero advantage.
Lay-up optimization - the stiffening plies are added to the sides of the tubes where they have the greatest effect in bending. They are feathered to distribute the loads into the structure. Cervelo also added more plies on the bottom of the down tube, the head tube and the top tube to distribute the loads from a potential head tube impact. Finally, Cervelo added Kevlar to that same area and down tube to prevent catastrophic failure. Razor-thin seatstays - the original Cervelo R3 was the first frame ever to incorporate ultra-thin seatstays. The new R5 series frames feature even smaller seatstay cross sections than before, further increasing the already legendary compliance for the rear wheel. The seat stays are almost unnecessary for the vertical loads, they only provide torsional stiffness. Therefore, Cervelo was able to design the R5 seat stays to act as leaf springs in the vertical plane while having a more standard dimension in the lateral plane for torsional rigidity. Thus it combines strength, comfort, torsional stiffness and minimal weight.
Combining the bigger head tube and BBright shell together left Cervélo with a lot more real estate to play with and they look to have used it well. The asymmetrical down tube is bigger up front and now extra-wide down below, the seat tube is similarly offset and broadened, and the non-driveside chain stay has nearly doubled in breadth.
In addition, while the driveside stay is still offset at the dropout to clear the cogs and chain, the non-driveside stay comes in straight on for better structural efficiency.
Other details include new carbon fiber dropouts, low-friction external cable routing with molded-in carbon housing stops, a carbon fiber seatpost clamp with titanium and aluminum hardware and a keyed shape to keep it from rotating on the frame (the seat clamp and three seat tube slots are offset from each other for more even clamping force), and a slightly altered frame geometry.