Proprietary aero seatposts need a dedicated interface to sit correctly inside the frame, and the MOST Gravel Plastic Seatpost Sleeve is the molded insert that handles that job on the Pinarello Grevil F. This is a genuine Pinarello factory replacement part, produced under Pinarello's in-house MOST component brand, that lines the seat tube pocket so the aerodynamic gravel seatpost seats in the correct position and clamps without shifting.

The sleeve slots into the seat tube ahead of the seatpost, giving the proprietary aero profile a matched surface to register against. That controlled fit is what keeps the post from rotating or slipping under load, and it protects the carbon seat tube from direct clamping contact. If your original sleeve is cracked, worn, or missing after a service, this is the part that restores proper positioning rather than trying to make a universal solution work in a frame that wasn't built for one.

This sleeve is certified for the Model Year 2026 Grevil F platform. Because it's shaped specifically for the Grevil F aero seatpost and seat tube geometry, it won't cross over to other Pinarello models or to round-post frames. Confirm your frame is the MY26 Grevil F before ordering, and match the part number below to be certain you're getting the correct interface.