How Much Does a Specialized SL8/SL9 Headset Top Cap Weigh?

Stock caps run roughly 10–16g depending on material (plastic or alloy). A topology-optimized titanium replacement arrives at 6.0g — roughly 4–10g lighter than stock.

Yes — the bolt threads into a star nut or expander below, preloading headset bearings. The cap distributes that force across the upper bearing race. A topology-optimized cap places thickness where the compression path runs and removes it from zero-stress zones. Structure and aesthetics share the same surface.

The cap has one simple load path — compression from a central bolt to a bearing seat ring. Topology optimization simulates that path and removes material from zero-stress zones. The organic rib pattern around the bolt hole is a byproduct of engineering logic, not decorative design.

The cap replaces the stock piece directly — same diameter, same bolt clearance, same bearing preload thread. It works with any standard star nut or stem expander already installed in the steerer. No adapter or modification needed. The bolt that threads through the cap into the expander is a separate item; TiNE also offers titanium headset bolts for SL8/SL9 if you want the full titanium stack above the bearings.