Coming from 80's BMX, I never had to install a star nut & never did it at all. I see it's simple but I'd still like other's input. How far down into the fork steerer tube, should the star nut be? Sette ST-113A Star Nut Setter ($12) mentions their tool sets it to 15mm & keeps it perfectly straight. Park Tool TNS-4 is cool but i'm not paying $35 for it.
What do you guys use to install it?
And I'm somewhat confused. As advised I'm not cutting the steerer tube until I find the right stem height. But I have to install my stem & test ride it, meaning the star nut must be installed right? Related to that, I heard the star nut cannot be removed if it is banged down too far. After I find the right height, how do I remove the star nut from the cut part of the steerer tube, so I can reuse it? I am gonna buy a second star nut also just in case. I figure it's good to have around & it's cheap. So what's the procedure?
And the purpose of the star nut seems to be to just hold the top cap on. Is there another purpose for it?
The star nut is there to snug the top cap and torque the headset. This is very important and you should watch a video explaining the procedure to tighten the top cap and stem.
If you are experimenting with fork lengths, you should cut the fork longer than you think you will need. Set the star nut a little below the end of the steer tube (15mm sounds good). You can ride your bike for a while with the steer tube longer than you need and move spacers above and below the stem until you find the height you want. When you are ready to make the final cut, tap the star nut 15mm below your cut and it will be in the correct place after you cut the steer tube. Once the nut is in, it can only go deeper so be careful not to set it too deep.
You could also pound the star nut all the way down and out the bottom and install a new star nut.
The star nut allows you to apply the correct preload to the headset by tightening the top cap down.
If you need to cut the steerer, you can just push the star nut further down.
I made a star nut setting tool with a piece of wooden dowel and a bolt. Its possible to do it by just hammering the star nut into the steerer tube - thread a longer bolt into it to give some leverage to help keep it straight. Having said that, I haven't had much luck doing that.
Your LBS would probably do it cheap - but if you're not in a hurry, the tool will probably cost about the same.
I just used the handle of a small screw driver that fit perfectly inside the steerer tube, and pushed it in. The star nut sets preload on the head tube bearings, so its pretty important. Push it down in maybe a 1/2" and assemble everything. Get a measurement for your steerer and push the star nut down a little further past the point you plan on cutting. i literally just did this an hour ago for the first time. Piece of cake
The LBS in my area charges $15 to cut a steerer and install a new fork. The star nut can be a little tricky to get centered without the correct tool.
There is another option and I am just putting it out there for information purposes... The reason for the starnut is to allow the top cap to preload the stem on the steerer tube and keep everything nice and snug before you tighten the stem. Once the stem has been tightened you do not need the top cap anymore. An alternate method would be to use a headlock. With a headlock you can apply the pressure to tighten you stem and then pull it out. Saves a minuscule amount of weight. Most people cut their steerer long to help keep resale value and having the steerer stick out pass the stem looks fairly ugly and that is why I don't use the headlock (even though I have one).
Last edited by FireLikeIYA; 09-16-2013 at 07:06 PM.
Reason: Added link to headlock
Killing it with close inspection.
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