Metal bit that fits into the top of the steerer tube...

[cyclingnolycra]

… is sticking out a bit (a solid half a cm!).

I have a carbon fork. I assume this isn't normal?
How might it have happened? Could it be overtightening the headset and thus "pulling" the metal bit out of the fork as a result?
I can still tighten headset fine and everything works, it just irks me and makes my bike look ugly as it makes my steerer tube look longer.


It seems pretty tight - is it ok to try to hammer it back down (after taking off the hub cap etc obviously?)


Thanks for help in advance.

[cogs19]

I’m guessing you mean the star nut. It can be knocked back into the steerer tube with the proper tool. Without the proper tool I know people use a screwdriver and a hammer. Finer minds here will let you know if that’s an acceptable hack or a potential disaster.

[biker jk]

I’m guessing you mean the star nut. It can be knocked back into the steerer tube with the proper tool. Without the proper tool I know people use a screwdriver and a hammer. Finer minds here will let you know if that’s an acceptable hack or a potential disaster.

If it's a carbon steerer there will be a compression plug not a star nut (except in some forks which have a metal insert for the star nut to grab).

A photo of the issue would be useful.

[Duck!]

One should never use a star nut in a carbon steerer, although I have seen it done.

The expander bung is likely not tightened enough, and been pulled out by a combination of excessive tightening of the top cap, the hammering effect of road shocks transferring up the fork, and the leverage effect from wracking through the bar and stem pulling the whole thing out.

Remove the top cap, loosen the centre bolt of the bung and knock it down so the top flange sits snug on the rim of the steerer tube. Firmly tighten the bung, then adjust headset.

[ValleyForge]

Remove the top cap, loosen the centre bolt of the bung and knock it down so the top flange sits snug on the rim of the steerer tube. Firmly tighten the bung, then adjust headset.

Except in the rare instance it's a DT Swiss top cap. They have a two-bolt expander system. First seats the expander, the second thread activates the expander. If you don't check the instructions, they do what the OP is having problems with.

[cyclingnolycra]

Thanks for the advice guys. I got really sick and am still recovering so will check it out once I'm recovered and can actually ride.