What nut is in this steerer please?

Discuss light weight issues concerning road bikes & parts.
Post Reply
stran11
Posts: 5
Joined: Tue Jul 31, 2012 2:10 am

by stran11

Hi All,

I have an older Look carbon fork (steerer is also carbon), I believe either HSC 1 or 2, that is too tall. I want to cut it down, but I am not familiar with the nut that is in place (please see photo). Can I simply hammer this nut down??

Thank you in advance,
Stanley
Attachments
thumbnail-1.jpeg

User avatar
themidge
Posts: 861
Joined: Fri Jan 13, 2017 4:19 pm
Location: Freeedooom!

by themidge

It looks like some kind of expander mechanism, which it should be with a carbon steerer. If it isn't totally rusted tight, you should be able to unscrew the central bolt (often quite far down, and recessed) and it will loosen and come out.
If it's something else, I'm not sure what you should do, and it probably shouldn't be in a carbon steerer. There was a thread about a star fangled nut in a carbon steerer here not so long ago, might be useful.

Edit: found it

by Weenie


User avatar
Calnago
Posts: 6545
Joined: Sun Nov 07, 2010 9:14 pm

by Calnago

Pretty sure it’s not the Cannondale type shown by @midge above. You need to unscrew the bolt (if you can), part way, then give it a little tap to try and loosen the other end that is pushing against the other side. If it’s loose then no problem. It should just drop out when you turn it over. Some penetrating oil may be required if things are really corroded.
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
Unlinked Builds (searchable): Colnago C59 - 5 Years Later; Trek Emonda SL Campagnolo SR; Special Colnago EPQ

c60rider
Posts: 344
Joined: Mon Feb 27, 2017 11:12 pm

by c60rider

themidge wrote:
Wed Apr 25, 2018 10:00 pm
It looks like some kind of expander mechanism, which it should be with a carbon steerer. If it isn't totally rusted tight, you should be able to unscrew the central bolt (often quite far down, and recessed) and it will loosen and come out.
If it's something else, I'm not sure what you should do, and it probably shouldn't be in a carbon steerer. There was a thread about a star fangled nut in a carbon steerer here not so long ago, might be useful.

Edit: found it
I have an old Look KG261 with the hsc fork and carbon steerer tube and had exactly this problem a few months ago where the central nut was stuck inside the expander. From memory I think I ended up just knocking it straight down which separated the two so it all fell out and I bought a new one. The one I bought was this https://www.sjscycles.co.uk/headsets/1- ... -expander/ though I didn't get it from here but 1inch expanders are few and far between for carbon forks. As yours looks a bit rusty in there I'd spray plenty of lube in there to help loosen it and just tap around the edges of the central bit. Don't smack the expander as it's the central bit that's jamming it against the inside of the fork and you risk damaging the fork. If that doesn't start to free it up then smack it a bit harder! It's only really small perhaps a couple of cm's long so it won't take much bashing to loosen it off. :thumbup:

In hindsight with mine I think what happened was the central nut and expander were wedged together so it wouldn't unscrew and the expander was slightly turning inside the fork steerer. It wasn't loose enough to pull out in one so I just knocked it out as above.

User avatar
jekyll man
Posts: 1388
Joined: Wed Apr 25, 2007 10:23 am
Location: Pack filler

by jekyll man

Have you tried it with the stem clamp undone?
It's more than possible the stem is compressing the steerer onto the bung enough for it to not release.
Official cafe stop tester

Fiery
Posts: 420
Joined: Sat Mar 16, 2013 9:21 am

by Fiery

A neat trick to pull out an expander plug that’s stuck even after it has been loosened is to ise the top cap and its bolt. Loosen the plug, loosen the stem bolts, install the top cap and bolt as you normally would and start tightening - instead of pushing the stem down, this will start pulling the plug out, and it will give you more leverage than just pulling it by hand.

stran11
Posts: 5
Joined: Tue Jul 31, 2012 2:10 am

by stran11

Thank you all for your input!

Through more searching and asking, I believe it's part of an expander that is missing a piece. Will try lubrication followed by gentle hammering.

by Weenie


Post Reply
  • Similar Topics
    Replies
    Views
    Last post