Road Cycling - "star-nut"

Hey Folks,

I have a technical question for those who know. My very capable local bike mechanic told me today that using a so-called "star-nut" with a carbon fork/integrated headset is not a great idea. Yet, this is how I received the bike from where I bought it. He suggested that a "plug" type set-up is the preferred method because, it doesn't cause so much wear on the carbon-fibre. Of course, I have no idea what he's talking about. He said I'd be okay for the time being, but, may want to consider a plug at a later time. So, for all of you tech-types out there, what's your opinion on this?

...and here's a picture from the George Washington Bridge while you're contemplating...:D

I don't know anything about your "star-nur" problem - sorry. That is one super-cool pic though!! :)

While we're at it can someone tell me how to extract a star nut?

That is correct. My new Quzo pro fork said not to use a star nut, only the expanding plug. This is true for a carbon fiber fork with a carbon fiber steerer tube, for a carbon fiber fork with an aluminum steerer tube, the star nut would be fine.

the manual for my fork is here. http://www.reynoldscomposites.com/Manual.pdf

If you have a carbon steerrer tube, it is suggest you do not use a star nut, if it is a alllow steerer on you're fork it should not be a problem. How to remove them I have no idea, normaly they are not removed.

To remove......from the top, just tap it down using a long screwdriver.....til it pops out of the bottom of the fork crown. Make sure you remove the front brake caliper before proceeding. If your steerer tube is aluminum or steel, keep the nut.

The metal star-nut will score the soft carbon fibre tube. A score-line can be the start of a fracture, even in composite materials.

ok heres the way I did it (accidentally). take off the top cap while your stem bolts are still tight. there you go. it'll pop right out.

MichaelW........you've got a good point there. Well then, if that's the case wouldn't it best just to leave it as it is and hope nothing catastrophic happens?

Phatman.......the star nut, if anchored properly, should not pop out merely by removing the top cap. The stem bolt being tight or loose is irrelevant.

If the steerer is full carbon I would return it to the place that wrongly put a star nut in it and demand a replacement fork. The structural(sp?) integrity of the steerer tube could have been compromised resulting in failure.
Kevin

Hi there,

...more naive questions. Is it possible that an aluminium/steel frame has a carbon steer tube? In other words, is the steer tube separate or inside the frame? Thanks again.

Steve

The steerer tube is the part at the top of the fork that comes through the frame that your stem attaches to. Most carbon fiber forks are not all carbon fiber(they have an aluminum steerer tube). Very few have a carbon fiber steerer tube. Is the part where your star nut is inside silver or black? You only need to worry if it is black.

Mr. Merckx........did your capable bike mechanic tell you that your carbon fork has a carbon steerer tube?? Did he actually take a look under the stem cap to verify this?

....I guess on the other hand sometimes you can tell by looking in-between the stem pinch bolts to see what kind of steerer tube is there.

Originally posted by George

....I guess on the other hand sometimes you can tell by looking in-between the stem pinch bolts to see what kind of steerer tube is there.

Or just loosen the top cap and pinch bolts and pull the stem off to check. It's fairly easy to determine carbon fibre from metal. Another thing you will want to make sure of is the angle of the gap on the stem's steerer clamp. Carbon steerers don't take too kindly to clamps that don't align along a perfect radial since they might cause stress risers to occur leading to delamination and/or failure of the steerer.

http://forums.mtbr.com/showthread.php?p=1189999

If the steerer is full carbon I would return it to the place that wrongly put a star nut in it and demand a replacement fork. The structural(sp?) integrity of the steerer tube could have been compromised resulting in failure.
Kevin

Many full CF steerer forks use an aluminum insert sleeve glued in that anchors the star nut.

CF steerer tubes without an aluminum sleeve should use a compression plug. BUT, in EVERY case, the manufacturers directions should be followed on how to set up a fork steerer, including what size of plug to use, the depth of the plug, and whether any spacers are needed above the stem. This varies considerably from fork to fork.

>90% of problem with CF steerers come from customers or mechanics who don't read the instructions.

that 2003 post date you see, yes that one at the top, that's 2003 and not 2008

Unless it's a Cannondale. Cannondale makes a star nut system on carbon steer tubes.

Edit: Holy crap. Brought back from the dead!

http://forums.mtbr.com/showthread.php?p=1189999

Why?

In his defense, 3 looks very similar to 8.

Just saying.

If the steerer tube is carbon, and there is a starnut in there, and NO Alu sleeve, return it. That's just asking for failure/death/nuclear explosion. Don't hammer it down further and don't try to pull it out. Replace the fork - whoever did that shouldn't have in the first place and should be beaten to death with a sock full of star fangled nuts. Carbon steerer tubes should use a compression plug, like this:

http://www.competitivecyclist.com/road-bikes/product-components/2008-problem-solvers-headset-compression-plug-1676.29.1.html

If the steerer tube is Alu, you're fine, leave it as is.
If the steerer tube is carbon WITH an Alu sleeve/star nut, you're fine, leave it as is.

While we're at it can someone tell me how to extract a star nut?

Here you go http://letmegooglethatforyou.com/?q=how+to+extract+a+star+nut

Here you go http://letmegooglethatforyou.com/?q=how+to+extract+a+star+nut

They didn't have Google in 2003.

/sarcasm <-- edit: added because the brilliance of BF is astounding. [/sarcasm]

Certainly did have Google in 2003. I remember using it in 1999 to research Y2k computer issues and the upcoming apocalypse.

http://www.google.com/corporate/history.html
http://en.wikipedia.org/wiki/Google

Certainly did have Google in 2003. I remember using it in 1999 to research Y2k computer issues and the upcoming apocalypse.

http://www.google.com/corporate/history.html
http://en.wikipedia.org/wiki/Google

Sorry, I thought the sarcasm was obvious enough, apparently I overestimated the intelligence of some posters.

I'll go back and edit to add a /sarcasm tag so that your poor brain doesn't get confused.