Specialized Seatpost Wedge Assembly

Specialized builds the current Tarmac and Crux frames without an external seat collar. Clamping happens inside the seat tube, where a wedge expands against the post as a single bolt draws it upward, and that is the entire job of the Seatpost Wedge Assembly from Specialized. This is the factory binder, sold on its own as a service part. The internal design keeps the top of the seat tube flush and uninterrupted, with no hardware protruding into the airflow behind the rider.

The bolt is steel and the torque spec is 55 in-lbf (6.2 Nm), worth treating as a hard number rather than a suggestion. A carbon post inside a carbon seat tube holds position through friction, so the answer to a saddle that creeps down is carbon assembly paste on the post, not another quarter turn on the wedge bolt. Overshooting the spec is how seat tubes get damaged, and a wedge gives you no warning before that point. Use a torque wrench and stop at 6.2 Nm.

Fitment runs across Tarmac SL8 complete bikes and framesets from the 2024 model year forward, including S-Works builds, Pro, Expert and Comp specs, and the team replica and artist collaboration paint schemes. The same wedge carries over to the Tarmac SL9 and the current-generation Crux, so a single part number covers road and gravel across the 2024 through 2027 lineup. What it does not cover is the Tarmac SL7 or SL6. Those frames use their own wedges with different hardware dimensions, and they are not interchangeable even though the system looks identical from outside the frame. Confirm which frame you are working on before ordering, because the older wedges carry separate part numbers.... Read More