The star nut is pressed into the steerer tube and allows the fork and headset components to be pulled into place in the frame’s head tube. If you have a new fork, or have just cut down the steerer tube, you may need to fit a new star nut.
You will need: a star nut fitting tube and a hammer.
Ideally, you should carry out this procedure with the fork off the bike. If you have an existing nut that needs to be replaced for any reason, the easiest way is to use a hammer and long bolt to push it out the bottom of the steerer.
It may be possible to fit a star nut using an appropriately sized bolt, hammer, and a top cap to help guide it in straight. However, dedicated tools make the job much easier. We also suggest using a brand new nut.
Wind the star nut as far as you can on to the fitting tool with the flare on the star nut pointing towards the handle of the tool. Brace the fork legs against the floor. Place the star nut into the steerer tube and use the hammer to tap the nut into the tube. Use a fair amount of force, but make sure to keep things straight.
Once the nut reaches the maximum length the tool allows, make sure the nut is straight. Unscrew the tool and your fork is ready to be reinstalled.