Swapping to a carbon-railed saddle on your Cervelo means swapping the seatpost head to match. The Cervelo Seatpost Head for carbon rails accommodates the 7mm x 9mm oval profile found on saddles from Fizik, Selle Italia, and other manufacturers who use carbon rails for weight savings. The stock head on most Cervelo aero seatposts clamps 7mm round rails, which won't secure the wider oval cross-section that carbon rails require for structural integrity.

The head assembly uses aluminum construction with a serrated steel friction plate sandwiched between the upper and lower clamp sections. Those serrations lock the saddle angle once you torque the bolt, preventing the gradual nose-down creep that plagues smooth-faced clamps over time. The serration pattern is fine enough to allow precise angle adjustment—you're not limited to coarse detents that force compromise positions.

A two-piece bolt design threads through the assembly, with hex fittings on both the insertion side and the receiving side. Reaching the 12Nm torque specification requires holding the receiving end with a hex key while torquing from the insertion side. Single-sided tightening won't achieve proper clamping force because the receiving end spins rather than resisting rotation. This is a common installation mistake that leads to saddle slippage, so take the extra step to engage both ends.... Read More