Remove your old star-nut and tap the top of your steerer tube. This might sound daunting, but we've made it super easy to do on your bike, without even removing your fork.
Remove your bar and stem
Use the OneUp star-nut puller to remove your old star nut
Using the self aligning steerer tap kit, tap a thread into your steerer until the tap bottoms out.
The OneUp EDC Tap Kit includes: A Star Nut Puller / "Go No-Go" Gauge,Tap and Tap Guide. (A Tap is a common cutting tool used to manufacture/cut internal threads)
See video and detailed instructions at https://www.oneupcomponents.com/products/edc-tap. Please read entire instructions and consult your local bike shop if you are uncomfortable with performing the tapping procedure.