Carbon steerer tubes on Cervelo and 3T forks require a specific approach to star nut installation. You can't just pound a star nut directly into a carbon steerer the way you would with aluminum or steel—the tube wall thickness and material properties don't support that kind of installation. The thin carbon walls need internal reinforcement to handle the mechanical grip and expansion forces that headset preload demands. The Cervelo Insert Kit provides the aluminum sleeve and epoxy necessary to create a proper foundation for headset adjustment on these forks.

The alloy sleeve bonds inside the steerer tube using the included epoxy, creating a reinforced section that accepts a standard steel star nut. Once the epoxy cures fully, the sleeve effectively converts the carbon steerer interior to an aluminum interface, allowing conventional star nut installation and the mechanical grip that preload adjustment requires. The sleeve diameter matches Cervelo and 3T fork specifications precisely, ensuring proper fit without play or interference with headset bearing alignment.

Installation requires attention to surface preparation and patience during curing. Clean the interior steerer surface thoroughly, rough it slightly for adhesion, apply the epoxy according to instructions, and allow adequate cure time before threading in the top cap bolt. Rushing this step risks a loose sleeve that can rotate or drop under preload tension—not something you want to discover mid-ride when your headset develops sudden play. The kit includes everything except the star nut itself, which you'll source separately based on your steerer tube diameter.... Read More