Cervelo S5 Ultegra Di2 Bike

The Cervelo S5 Ultegra Di2 Bike answers one question with the entire machine: how much speed can a road bike deliver before you even start pedaling harder? Cervelo has been building dedicated aero road bikes for two decades, and the current S5 represents the most resolved iteration of that work. Every element — frame, fork, cockpit, seat tube, and wheels — was co-developed as an integrated system rather than assembled from independent parts. The goal was to reduce aerodynamic drag at every contact point, and the design reflects that intent in every detail.

The carbon frame features an asymmetric seat tube shaped to match the profile of the rear wheel, eliminating the turbulence-generating gap that a round seat tube creates next to a deep-section wheel. Up front, the fork legs and head tube are deeper than the previous generation, and the one-piece integrated carbon bar and stem — Cervelo's Plus-Four concept — narrows 4cm at the hoods relative to the drops. That geometry reduces the frontal area your upper body presents at speed, where aerodynamic drag is the decisive variable. Cervelo's own testing places the current S5 at 6.3 watts faster than its predecessor. Despite an increase in surface area to achieve those gains, the frame is 124 grams lighter than the previous generation — a product of refined carbon architecture, not a tradeoff with stiffness or strength.

The Ultegra Di2 build pairs Shimano's 12-speed electronic groupset with a 52/36T crankset and 11-34T cassette, running on a ceramic bottom bracket. Ultegra Di2 delivers consistent, instant shifting under any load — the same actuation logic and electronic precision as Dura-Ace Di2, with the long-term reliability that holds its adjustment over thousands of kilometers of hard riding. A power meter comes standard in this build, integrated into the crankset, removing a purchase you'd otherwise budget separately. The Reserve 57|64TA carbon wheelset with DT Swiss 240 hubs completes the package: a deep front-and-rear combination engineered for aerodynamic performance, with Swiss hub precision and engagement quality built for the long haul. The S5 is available in Five Black and Carnelian across six sizes from 48 to 61cm, and every size combination is fully UCI-legal for competition.

Design Benefits

1. Integrated aero system — frame, fork, cockpit, and wheels co-designed for aerodynamic performance rather than optimized as separate components
2. Plus-Four cockpit — one-piece carbon bar/stem narrows 4cm at the hoods vs. the drops, reducing frontal area at speed without compromising descending grip position
3. Asymmetric seat tube — shaped to match the rear wheel profile, eliminating the turbulence-generating gap that a conventional round seat tube creates alongside a deep-section wheel
4. Power meter standard — integrated into the crankset, removing a typical separate cost from the build equation
5. Reserve 57|64TA with DT Swiss 240 hubs — performance wheelset spec that pairs deep-section aerodynamics with Swiss hub precision and longevity

Final Take

The S5 Ultegra Di2 is the entry point into Cervelo's flagship aero road bike platform — and it arrives more complete than most bikes at this level. You're getting the same frame and fork architecture as the top-tier S5 builds, the same integrated cockpit, the same Reserve wheels, with Shimano Ultegra Di2 handling the shifting. Power meter included. Ceramic bottom bracket. Nothing left to upgrade before the first race. For a rider who's serious about free speed, who wants a properly integrated aero machine rather than an aero frame with budget parts bolted on, the S5 Ultegra Di2 makes a compelling case for where it sits.