This is Wolf Tooth’s compression plug for 1 1/8" threadless carbon fork steerers. It provides internal support so you can properly preload your headset and safely clamp your stem on carbon steerer tubes. Key Functional Details Designed for 1 1/8" threadless steerers Fits steerer inner diameters from 23.2mm to 24.2mm Aluminum construction Used to preload headset bearings before tightening stem bolts Silver finish Wolf Tooth headset system compatible Compatibility & Technical Notes For carbon steerer tubes only Fits 1 1/8" steerers with 23.2–24.2mm internal diameter Works with standard threadless headset systems NOT for aluminum or steel steerers (use a star nut instead) Requires a 4mm or 5mm hex key for installation (depending on setup) Must be installed below top of steerer to allow proper preload Service / Ownership Context This is a small but critical part. Proper installation prevents carbon steerer damage and ensures smooth headset adjustment. Fit & Use Signals Good Fit: Bikes with carbon forks and 1 1/8" threadless steerers. Not A Fit: Aluminum or steel steerers, tapered lower sections, or steerers outside the listed inner diameter range. This is mandatory on carbon steerers. Never use a star nut in carbon. Biggest customer mistake is trying to reuse an old plug that’s already chewed up, or installing it too shallow so the top cap bottoms out before preloading bearings. Also common: people crank the top cap thinking it holds the stem. It doesn’t. Top cap only sets bearing preload — stem bolts do the holding. Measure steerer ID if unsure. Some forks run tight or loose. This fits 23.2–24.2mm — outside that range it won’t expand correctly. Install depth matters: plug should sit a few mm below top of steerer so the top cap can pull properly. Failure points: overtightening the expander bolt, stripping the internal wedge, or crushing lightweight steerers with excessive stem torque. Who this is really for: anyone running a carbon fork with a standard 1 1/8" steerer. Who should avoid: metal steerers — use a star nut instead. Typical service issues: headset won’t tighten because plug is slipping, top cap bottoms out, or customer forgets to loosen stem bolts before preloading. Riders don’t think about this part until something creaks. When installed right, it disappears. Mechanic advice: lightly grease the plug body, don’t over-expand, torque stem bolts to spec, and always preload headset before clamping stem.
