How to fit a star nut

Step-by-step guide to replacing a star nut

How to fit a star nut

The star fangled nut — or ‘star nut’, as it’s known — 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 your steerer tube, you may need to fit a new star nut.

Watch the video above to find out how, while written instructions are listed below.

How to fit a star nut

Tools for the job

  • Star nut fitting tool 
  • Hammer

1. Preparation

Ideally, you should carry out this procedure with the fork off the bike. If your steerer needs to be cut down then do that before installing the nut. You can see our video guide on how to do that here.

If you have an existing nut that needs to be replaced, the easiest way to remove it is to use a hammer and long bolt, metal rod or drift to push it out the bottom of the steerer.

The easiest way to remove a star nut is to use a hammer and long bolt, metal rod or drift to push it out the bottom of the steerer
The easiest way to remove a star nut is to use a hammer and long bolt, metal rod or drift to push it out the bottom of the steerer

Note: It may be possible to fit a star nut using just an appropriately sized bolt, hammer and a top-cap to help guide it in straight. However, dedicated tools make the job much easier, and are relatively inexpensive. We’d also recommend using a brand new nut rather than attempting to reuse an old one.

2. Fitting

Wind the star nut as far as you can onto the fitting tool, with the flare on the star nut pointing towards the handle of the tool.

Wind the star nut onto the fitting tool, as far as it will go
Wind the star nut onto the fitting tool, as far as it will go

Brace the fork legs against the floor, positioning a rag or other padding to protect the dropouts.

Place the star nut into the steerer tube and use the hammer to tap the nut into the tube. You’ll need to use a fair amount of force, but try to keep the tool and nut straight, especially early on in the process.

Place the star nut into the steerer tube and use the hammer to tap the nut into the tube. Try to keep the tool and nut staight
Place the star nut into the steerer tube and use the hammer to tap the nut into the tube. Try to keep the tool and nut staight

Once the nut reaches the maximum depth that the tool allows, check that the tool is straight and flush to the tube. If it isn’t, a few more light taps should help the tool automatically correct this.

Unscrew the tool and your fork is ready to be reinstalled.

Oli Woodman

Section Editor, UK
With more than 10 years of experience riding mountain bikes, Oli knows the good from the bad when it comes to gear. He's a total bike nerd and loves few things more than fettling with spangly riding bits. Also, he seems to have a talent for crashing hard but emerging unscathed.
  • Discipline: Mountain
  • Preferred Terrain: Loamy singletrack
  • Current Bikes: Marin Pine Mountain, Pinnacle Dolomite
  • Dream Bike: Honda RN01
  • Beer of Choice: Corona
  • Location: Bristol, UK

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