It is difficult to point to one aspect of a bicycle frame as being more comfortable than another. It is even more difficult to measure comfort since every rider is different. However, with the Ultra Thin Seat Stays of the R series, you can see what Cervelo has done to make your ride more comfortable in practice.
Our engineers approach ride quality with common sense and practical applications of engineering. If you want more deflection in a given plane, use less material. In terms of comfort, less material in the vertical plane not only offers higher vertical compliance and vibration absorption, but also spares unnecessary weight. This common sense approach to rider comfort is evident in the Ultra Thin Seat Stays of the R series frames.