With the original R5ca, Cervelo pushed the lower weight boundaries of a production frame to an average 700g. Now, they’re pushing it again, while maintaining the high frame stiffness and bringing in some interesting new technology.
Coming in at a claimed 667g (size 54, with paint and hardware no less), this frame went through 93 different frame shapes and 279 FEA sessions to become the Rca. When Cervelo put their standard Squoval (square oval) tubed bikes in the wind tunnel, they say it performed surprisingly well given aerodynamics were never a major consideration. So, they decided to see how far they could push it without giving up the stiffness and comfort they already had. And, per usual, they wanted to make it lighter.
Both took a lot of computer aided help, using custom FEA software that considered each and every ply of carbon’s size, placement and orientation. Then, it required some new materials, too. The result? An insanely lightweight bike that carries an equally insane $10,000 frameset-only price point…
Compared to the R5ca, they’re claiming a negligible 3% increase in torsional stiffness and 3% decrease in bottom bracket stiffness.
The claimed weight is an average, with a +/-20g allowance. They’re using the 54 as their callout since that’s the size used by most of the Garmin team riders.
The frameset uses two new technologies to get the weight down without sacrificing strength and stiffness. Within the frame, they incorporated 3M PowerLux resin system into certain parts of the frame, which puts “nano-silica” into the resin to reinforce the space between the fibers. This improves interlaminar shear and compression strength, and allows for less material at the same strength.
The fork gets a Integran/PowerMetal Nanovate treatment – a coating of nano-fied grains of nickel on the steerer tube that increases both strength and ductility without adding weight.
To improve aerodynamics, the leading edge was rounded on the downtube, headtube and seatstays and tweaked the trailing corner radii. The new shape is called Squoval 3.
The shapes, though, are not universally applied. Using lessons learned from the P5 TT/Tri bike, “AeroZones” were used to selectively maintain the original Squoval shape higher on the downtube where it’s closer to the front wheel, and the new shape is further down where the wind hits it more directly. They also turned the ellipse shape by 90º at the bottom of the seatstays, putting the plane more inline with air flow.
Overall, this leads to improved airflow over the complete bike as a system, and they claim it sheds 74g of drag from the R5ca frame, equivalent to 7.4 watts. It’s important to note that the aero improvements are at yaw angles up to 20º, not just straight on.
Like the original Project California, these are hand-made one at a time in CA.
Cable and wire ports are universal and future proof. Just pop different stops into place and you’re ready for whatever. They click into the frame to hold tight, and running everything internally keeps the airflow clean.
Mechanical stops are quite nice looking, too, and they’ll have plugs for hydraulic lines, too.
Another weight saving trick is the hollow carbon fiber dropouts. Normally, carbon dropouts are solid pieces made from chunked up carbon pieces pressed into a mold, then they’re bonded into the stays. Cervelo took an opposite approach, making them hollow and inserting the stays into the dropouts. This saves a bit of reinforcing material on the stays (saves 5g) and lets them run the wire/cable directly out the back for a streamlined look.
The frame design and stop placement minimizes cable bends, which should improve shifting, and internal cable guides aid installation without having to remove any other parts.
A strong neodymium magnet is molded into the frame, totally flush, on the driveside of the bottom bracket shell, positioned to pick up the signal from most popular power meter cranks. It uses their 79mm-wide BBRight press fit bottom bracket standard, which uses an 30mm spindle that’s 11mm longer than a standard BB30 crankset.
In addition to the material updates, internal frame reinforcements support the thinner walls in high stress areas, namely:
- down tube at head tube
- seat tube at top tube
- above the bottom bracket shell
They say this provides the same benefit as thicker tubes but saves a few grams. Their trademark pencil thin seatstays combine with “ComfortPly” layup design to add a bit of vibration and bump absorption.
On the downtube and other key areas, more material is placed on the sides of the tubes to resist lateral stresses.
The framesets will retail for $10,000 and start shipping March 18. Sizes are 48/51/54/56/58/61. Full geometry and more info should be up on Cervelo.com soon.