Cervelo SLC-SL

Fabian Cancellara uses the SLC-SL aerodynamics to stay clear of the sprinters and win stage 3 of the 2007 Tour

Fränk Schleck speeding towards Alpe d'Huez on his prototype SLC-SL

Fränk Schleck winning atop Alpe d'Huez on the SLC-SL

Outstanding aerodynamics – Like the Soloist Carbon, the SLC-SL uses the best airfoil shapes designed for bicycle speeds. Cervélo doesn’t use standard NACA (now NASA) airfoil shapes, as they are mostly designed for speeds much higher than are attained on a bike.

Light, but efficient – It is easy to make a light frame, just use less material. But the SLC-SL is light by using material in the right places, rendering stiffness properties in the BB and in torsion that are even 5-10% higher than the already leading-edge Soloist Carbon.

New profile downtube - Our work into improving the downtube and headtube on the P3C has directly benefited the Soloist Carbon and SLC-SL.

Horizontal teardrop-shaped sloping toptube - Since the toptube has a slope to it, the aerodynamics can be improved by giving it the proper airfoil cross section in the direction of the airflow.

Stealth aero headtube – While the headtube may look round at the front, this is an optical illusion. The headtube is ultra thin and only 1mm wider than the P3C headtube. Although the leading edge is kept straight, the sides neck down in the center section, resulting in a very good airfoil shape around the headtube in combination with a classic side profile.

Oversized bottom bracket area – The increased volume of the bottom bracket area provides even greater bb stiffness so that Jens can continue to power away from the competition. The smooth contours of the BB volume help both for this BB stiffness and also for its strength as the fibers have a much more continuous path to transfer the loads better.

Wolf seatstays – The seatstays have an asymmetric design from our Wolf family of airfoil shapes, designed for optimal airflow around a thin frame member interacting with a spinning wheel.

ICS Internal Cable Stops - The best internal cable stop system available. Easy to install, easy to service, easy to keep clean and improved aerodynamics.

Lighter frame - While the Soloist Carbon is among the lightest frames in the ProTour (as determined by independent sources like the French magazine Le Cycle), the SLC-SL shaves another 200g off the weight to become one of the lightest frames in the world (real weight, not claimed weight) and the only in that select group with such aerodynamic features.

Higher bottom bracket and torsional stiffness - The Soloist Carbon is Jens Voigts favorite bike in 2006. So maybe there was no need to increase the bottom bracket and torsional stiffness of the SLC-SL beyond that level, but nonetheless we have raised it another 5-10% for optimum handling and safety.

When Cervélo first started using tube profiles as designed by the National Advisory Committee on Aeronautics (NACA), it caused quite a stir in the bike industry. These tubeshapes are the result of years and years of research and do a very good job of reducing the aerodynamic drag created by the tubes. We manufactured extrusion dies specifically for these NACA profiles, as it was the only way to get the tube shapes accurate.

But while NACA profiles are good, they are not ideal for bicycles. NACA profiles are generally designed for higher speeds, even those designed for "low-speeds" were made with speeds in mind that go beyond most cyclists' abilities. Therefore we have turned our attention to designing our own airfoils at Cervélo in the past few years, improving wherever possible on the foundation laid by NACA. The result is the latest family of airfoils, from the shapes used on the Soloist, Dual and P series TT/Tri bikes to the Wolf shapes optimized for frame and fork shapes adjacent to spinning wheels.

While difficult to detect visually, the tube shapes and aspect ratios on the Soloist Carbon and SLC-SL offer small improvements compared to the standard Soloist Team. The downtube has the same profile as the P3C, while the seattube is tweaked and repositioned to take advantage of the possibilities the carbon offers us. A great improvement was made in the shape of the headtube airfoil section and the way it blends in with the downtube and toptube.

The headtube shape is slightly different than the P3C due to different stiffness-weight-aerodynamics requirements, but it is still a very big step forward compared to regular headtubes, both in terms of narrowness (only 1mm wider than the P3C) and aerodynamic cross section shape.