The Cervélo S2 105 bike delivers S3 performance at a price barely higher than Cervélo's S3 frameset. And the S3 is a redesign of the category-defining S-series frame, the Soloist, which really put Cervélo on the road racing map. The S2 shares a frame with the S3, with the departure being at the fork. The S2 fork is a simpler build, which drops the price nicely.
This new Cervélo S2 applies lessons learned throughout Cervélo's line. The ultra-thin seat stays, something started in the R-series, offer great vertical compliance. The seat tube cutout, from the P-series, improves aerodynamics around the rear wheel. The BBright bottom bracket, from the R's, increases stiffness and improves power transfer. The down tube has been shaped, and the bottle bosses placed with actually mounting bottles in mind, learned from the S5; this way, when you have bottles on your bike, they work with the down tube to better move air around them. This improves aerodynamics. The R-series innovation of a 1 1/8" to 1 3/8" tapered steerer tube, with the head tube shaped to match helps improve steering control, and cornering prowess increases. And the internal Future Proof cable routing adds to the aero and makes it easy to install, replace, and switch cable systems, be they mechanical, electronic, or hydraulic.
To keep price down and performance high, most of the components are from Shimano, with a mix of 105 (brifters and derailleurs), and Tiagra (ten-speed 11-25 cassette and chain). Cervélo installs the FSA Gossamer BBright 50/34 compact to maximize the BBright benefit. They also opt for steering from partner 3T, the ARX stem mated to the Ergonova bar.
Cervélo wanted to have their frames fit a huge variety of body sizes and types. To do this, they studied databases of body dimensions. They don't offer different men's and women's models because their sizing allows for people to pretty easily determine what size they need by looking at the stack and reach dimensions. When combined with a sloping top tube, each frame can accommodate a fairly wide range of body sizes.
The Cervélo S2 105 bike gives you a bike that has the aero profile of a time trialist with the geometry of a road racer.