Bicycle Mechanics - Slipping STAR NUT in steerer tube?

Hello!

Problem: newly installed STAR NUT slips in 1 1/8th threadless steerer tube...ie, turn headset screw, it pulls star nut upwards!

preface: so i am a somewhat amateur home bicycle mechanic....have 5 bikes, work on them all myself. anywho, i have a star nut installing tool, and have installed two star nuts before with no issue whatsoever.

However, with a new fork i just cut myself, after i installed the star nut and put the headset cap on then screwed the headset screw into the star nut, the star nut gets pulled upward....i noticed it also dosn't take much effort to push it down either!

NOW i will also say, i bought this starnut from the local LBS because id like to think its nice to support your LBS....BUT i specifically asked for a 1 and 1/8th inch starnut....and from previous star nut installations (well, 2) it took significantly more effort to install...

BASICALLY im thinking the LBS gave me a 1 inch starnut...that or a shoddy quality starnut....OR MAYBE ITS SOMETHING ELSE I AM UNAWARE OF??? thats why i am asking here. if you all think my LBS made a mistake (which has happened before) then i am forever boycotting said LBS and buying everything online.

I suppose it's possible that you got a 1" starnut but it's also possible you got a starnut for an aluminum steerer which has thicker walls than a steel steerer. Take the fork back to the LBS and find a nut that fits properly.

you are probably right in respect to getting one for aluminum. my fork is steel. thanks

If it's slipping, pull it out and buy another one. it's not like they are expensive. If it's your LBS's fault boycott them if you want but this is a cheap fix. If for some reason you can't get it out, push it down and out of the way and put in another one.

I had this problem once and even my LBS had a hard time finding a star nut that was big enough and wouldn't slip. Another option is to go with an expander plug designed to be used in carbon steerers, but they are quite a bit more expensive and heavier than a star nut.

I had this problem once and even my LBS had a hard time finding a star nut that was big enough and wouldn't slip. Another option is to go with an expander plug designed to be used in carbon steerers, but they are quite a bit more expensive and heavier than a star nut.
The problem with using an expander is that most are intended for carbon steerers which have even thicker walls than an aluminum steerer so they won't expand enough to grip a steel steerer. There are expanders designed for steel steerers (Profile Designs makes one) but you have to specify that type.

I'm not sure this is a good idea or not....but
You could place the star nut on a flat surface and give it a sharp whack with a mallet. The more the cone flattens out, the larger the diameter.
I guess the drawback is that it has less of an angle to bite in.
Just a thought.

I'm not sure this is a good idea or not....but
You could place the star nut on a flat surface and give it a sharp whack with a mallet. The more the cone flattens out, the larger the diameter.
I guess the drawback is that it has less of an angle to bite in.
Just a thought.

+1

I had this problem once and even my LBS had a hard time finding a star nut that was big enough and wouldn't slip. Another option is to go with an expander plug designed to be used in carbon steerers, but they are quite a bit more expensive and heavier than a star nut.

Who cares.

Once the preload is set the entire stack, expander and top cap can be tossed anyways.