With the development of the 2018 Cervelo R5 premium road frameset, a new Squoval Max tubeset was used to optimize aerodynamics of the R5. The new seatube shape has a d-shape, or flatback design, as does the new SP-18 carbon seatpost. Part of the improved aerodynamic profile of the frame included a new integrated wedge seatpost fastening system that sits at the rear of the post, where the seatstays meet the seattube. A small receiving zone in the frame accepts this Seat Post Clamp For R5, which is actually just the expanding wedge device.

The wedge comes in two sizes, based off frame size. The 48 and 51cm frames share a smaller size wedge, while the 54-61 sizes use the large wedge.