bolt inside carbon steerer



zaku

New Member
Jun 23, 2004
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i don't know the exact term how you call this but it's about the bolt that's clamped on the inside of the steerer tube so we can tight/tension the stem/steering.

the question is how do we push it further into a carbon steer tube since i'll be cutting a part of the tube which needs that bolt to be further in.
i see a hex kind of shape on that bolt clamp. so is it as easy as just using an allen key and screw it clockwise so it will go in further?
i don't know how to do this on a carbon steerer just make sure i won't be breaking the tube..

thanks in advance
 
While there are speciality tools designed for installing a STAR NUT, you can "push" the STAR NUT further into the steerer with a wooden dowel (e.g., a 6" section from a broom handle) & a hammer ... TAP the end of the dowel GENTLY because it doesn't take too much force to move the Star Nut downward into the steerer!
 
If it's a carbon steerer, it should have a compression plug instead of a star nut. The star nut may cut the fibers in the steerer tube, which would be bad. So if you find a star nut in there you may want to get a mechanic to make sure things are OK with your carbon steerer tube...

Also, if it's a plug you'd want to loosen it a little to get it to let go of the wall of the tube before you try to tap it in. On some models you loosen the plug by turning the 5mm bolt in the center of the top cap counter clockwise. The cap itself sometime tightens independently of this using a larger (eg. 6mm) key.

Edit: Sounds obvious, but be careful cutting that tube, too. They make special saw guides and stuff like that for this specific job, the idea being that there are no "do overs". Good luck!
 
Forgive me ... as noted by grv, with your carbon steerer, you will hopefully not have a Star Nut!

Both of the forks that I have which happen to have carbon steerers (all the rest have aluminum or steel -- older ROAD stuff, to say the least -- so, that's my lame excuse for not responding correctly) have a "plug" which was epoxied inside the steerer (one has an integrated "cap" that faces the top edge of the steerer) after it was cut RATHER than using a compression plug.

BTW. A common practice would be NOT to re-cut the steerer BUT re-stack the excess spacer above the stem.
 
Great advice by all. Yes most likely it is a compression plug. Just to be a know it all a very few models of bikes do have star nuts in carbon sterer tubes, Cannondale uses that system though it's not your average star nut, it's a proprietary unit made just for their slice forks. Measure a couple of time, check it with all your spacers before cutting. Even better ride it around some with the spacers on top of your stem before finalizing it all with a cut. Basic fine tooth hacksaw worked slowly will do the job fine.
 
thank you guys for the advices.

indeed inside my carbon steerer is like a compression plug. it has a 6mm bolt in it.
i tried to loosen the bolt completely (i even removed it) and tap the plug in. but it seems to be stuck on the wall of the steerer. i don't want to tap it too hard that might break the steerer...? is it usually that hard to tap the plug in when the 6mm bolt is completely removed? or is it just mine that's kinda stuck? or should i spray some wd40 in it?
 
zaku said:
thank you guys for the advices.

indeed inside my carbon steerer is like a compression plug. it has a 6mm bolt in it.
i tried to loosen the bolt completely (i even removed it) and tap the plug in. but it seems to be stuck on the wall of the steerer. i don't want to tap it too hard that might break the steerer...? is it usually that hard to tap the plug in when the 6mm bolt is completely removed? or is it just mine that's kinda stuck? or should i spray some wd40 in it?
FWIW. The "compression plugs" that I have are the type that FSA included with their headsets a half-dozen years ago, or so. NOTHING remains in the steerer ... it is removed, en toto, as a unit that includes the top cap ... and, the steerer is subsequently EMPTY when it is not in place.

So, I think what you are looking at is a plug which was epoxied in, as on the two forks I mentioned I have -- if so, then (AFAIK) you cannot change the plug's location by tapping it in further!

How much lower do you want to mount your stem?
 
If your bearing pre-loader expander is manufactured like most are:

1. With the compressor cap removed, replace the center screw in the expander cone. Screw it in just a few turns; not even finger tight is required.

2. Try gently rapping in the screw head with a wood block. This should dislodge the expander cone from the segments that grip the inside of the steerer tube.

3. Gently pull up on the screw and see if the expander cone starts pulling the whole assembly up out of the steerer tube. If not, a little WD-40 or light oil may be needed. Be sure and clean all the lubricant off the steerer/expansion components prior to re-assembly.
 
em.. so looks like mine is epoxied? i'm looking to lower bout by an inch. and for aesthetic reasons i prever not to have too much negative rise personally.

anyway i took a picture of it might be easier for you guys to see what's exactly in.

pic with bolt removed:

DSC00775.jpg
 
thats not a star nut. you should be able to put the bolt back in a little and yank it out. might be just frozen in place for some reason.

--brett
 
alfeng said:
Forgive me ... as noted by grv, with your carbon steerer, you will hopefully not have a Star Nut!
until at least the six13 models all canondales came with star nuts in the full carbon forks. i don't know if they retained this after the six13's as i haven't worked on one of them.

they were completely fine. i raced a caad7 with slice premium full carbon with the star nut set out of the factory for 2 seasons.

--brett
 
em.. so looks like mine is epoxied?

I don't see any sign of excess epoxy.

Have you fully loosened your stem clamp screws?