Wilier's reimagined Cento1 SR follows an increasingly common trend among top-end race bikes: convergence. In the past few years, many companies had two high-end race bikes: one as light and stiff as possible, the other designed in a wind tunnel to ensure an aerodynamic advantage.
While that trend remains, companies are beginning to blend aerodynamic characteristics into their lightest frames. Scott may have been the first brand when it released the Foil last year. Now, two other bikes are showing similar characteristics: Trek's just-released Madone 7 and Wilier-Triestina's new Cento1 SR.
Like the Scott Foil and Trek Madone 7, Wilier's Cento1 SR uses aero-shaped tubes that have had their tails truncated—sometimes called Kamm Tails—on the fork and seat tube/mast. Theoretically, the careful shaping has nearly the same aerodynamic characteristics as a wing-shaped airfoil in a headwind, even though the tail itself has been cut off. The benefit of using a Kamm Tail tube is that designers wind up with a more traditional shape, which is stiffer, lighter, and can be made more compliant than broader aero shapes.
All New Frame
Tubes shapes are just one element on a totally redesigned bike, however. Gone are the organic, rounded lines of the previous Cento1. In their place are bigger tubes and many more squared edges, all enhanced by a paint scheme that evokes Tron. The company also used more 60 Ton carbon than in the Cento1 Superleggera. The material, combined with the bigger tubes, improves stiffness.
Wilier also built more stiffness into the fork and bottom bracket. The fork uses a new tapered steerer fork from 1-1/8” down to 1-1/4" (the old Cento1 used a straight 1-1/8" steerer), with a crown that flows smoothly into the down tube. At the lower end of the frame is a new BB386EVO bottom bracket shell. The previous Cento1 also used a press-fit system with different cups for the various crank axles. BB386EVO, essentially a wider BB30 shell which was a co-developed by BH, Wilier, and FSA, is even bigger and optimized for a 386EVO crank with 30mm axle. However, with the correct conversion kit, the frame is compatible with almost all cranks, aside from BB30 and square-taper models.
One of the primary reasons to use the BB386EVO is to provide lots of area to attach big, stiff tubes. The Cento1 SR's non-drive chainstay is about 65mm high and 25mm wide where it joins the BB; the downtube about 80mm across.
Wilier also adjusted the geometry. Head tube lengths are mostly shorter in every size, except small, which is a bit longer to make the per-size jumps more uniform than they were in 2012. The medium size receives the biggest geometry change: the seat and head tube angles are both a half-degree slacker, making the top tube a bit longer.
Down tube barrel adjusters on the top of the tube allow for easier shifting tweaks with mechanical drivetrains.
One Frame for Two Shifting Systems
Joining yet another increasingly common trend, the Cento1 SR frame has internal routing for either electronic wires or mechanical cables. For mechanical shifting, the company built barrel adjusters into the access panel on the top of the down tube where they're easy to thumb while riding—just be careful your fingers don't slip into the tire. The bottom bracket cable guide has a large radius to reduce friction with mechanical shifting.