# star nut on carbon fork makes it unsafe?



## josephr (Jun 17, 2010)

My friend Eddie picks up a craigslist special on a 5 year old Cannondale Synapse with a full carbon fork. good riding bike and starts getting the standard head tube creak. Henry pulls apart the stem and down in the steertube of the full carbon fork is a star nut that's been rammed down the steertube instead of a compression fitting. 

Henry advises this is an incorrect installation and the carbon fork is absolutely ruined and should be replaced, and despite no noticeable crack in the steerer, the bike is unsafe and should not be ridden until the fork is replaced.

I'm not a bike mechanic, and while I like to think I err on the side of safety, this advice seemed a little overly cautious.

Thoughts???
Joe


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## krisdrum (Oct 29, 2007)

Henry is spot on. Not advisable to ride as is. You have no idea what kind of damage the starnut did as it was installed into the steerer tube. If you do ride it, it is at your own risk. I assume Henry works at a shop, so he could be held liable if he did not raise the issue to you and make very clear there is risk involved.


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## josephr (Jun 17, 2010)

Thanks for setting me straight. I feel pretty bad for Eddie as he's a super-nice guy and leads a lot of club-rides and really takes time with new riders. However, he lives on a very tight budget and he really struggled with this bike and he's in the middle of moving his trailer, so a new fork is going to be a big hit to his wallet right now. 
Joe


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## vagabondcyclist (Apr 2, 2011)

josephr said:


> Thanks for setting me straight. I feel pretty bad for Eddie as he's a super-nice guy and leads a lot of club-rides and really takes time with new riders. However, he lives on a very tight budget and he really struggled with this bike and he's in the middle of moving his trailer, so a new fork is going to be a big hit to his wallet right now.
> Joe


Yes, but crashing will be an even bigger hit. I don't mean to be rude, but there's no way to know how damaged the steerer tube is and rest assured it is damaged. Given that it is creaking now it's only a matter of time before it cracks, splits, etc. if Eddie keeps riding it.


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## QuattroCreep (Nov 30, 2009)

No, don't freak out yet. Cannondale does have some models of bikes that came with carbon forks and star nuts. Your best bet is to have your friend call a good Cannondale shop or write an email directly to Cannondale and ask if it is OK.


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## josephr (Jun 17, 2010)

QuattroCreep said:


> No, don't freak out yet. Cannondale does have some models of bikes that came with carbon forks and star nuts. Your best bet is to have your friend call a good Cannondale shop or write an email directly to Cannondale and ask if it is OK.


Wow...that's different news. Smart idea. He's not even sure what year it is. Either way, I think he's glad he's got a back-up bike!
Joe


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## josephr (Jun 17, 2010)

vagabondcyclist said:


> Yes, but crashing will be an even bigger hit. I don't mean to be rude, but there's no way to know how damaged the steerer tube is and rest assured it is damaged. Given that it is creaking now it's only a matter of time before it cracks, splits, etc. if Eddie keeps riding it.


You're soooo rude! I swear, I can't believe the amount of rudeness you put into just a few shorts words! 

No...not rude...that's what I love about forums is that I can post something question that might seem dumb in some crowds or to the wrong crowd where no one knows for sure and quickly there'll be three or four good answers which help bring contextually relevant knowledge and experienced based judgement to the problem resolution process. 

Anything is better than scraping a fellow cyclist off the pavement!
Thanks!
Joe


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## QuattroCreep (Nov 30, 2009)

josephr said:


> He's not even sure what year it is.


Check out this site. BikePedia, QuickBike Complete Bike Specs

Select a year, then a brand, finally a model. Poke around for a while looking at the different paint schemes, and builds for different years and models of that bike. You should be able to narrow it down to a year and build level pretty easily.

If it is between 2008-2012 you can check here:
Bike Archive


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## krisdrum (Oct 29, 2007)

QuattroCreep said:


> No, don't freak out yet. Cannondale does have some models of bikes that came with carbon forks and star nuts. Your best bet is to have your friend call a good Cannondale shop or write an email directly to Cannondale and ask if it is OK.


I have NEVER seen a carbon steerer tube fork that calls for a starnut instead of a compression plug or some other set-up (usually a nut epoxied into place). It is worth reaching out to C-dale, but I have a feeling if the fork steerer is carbon, your friend is SOL.


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## QuattroCreep (Nov 30, 2009)

krisdrum said:


> I have NEVER seen a carbon steerer tube fork that calls for a starnut instead of a compression plug or some other set-up (usually a nut epoxied into place). It is worth reaching out to C-dale, but I have a feeling if the fork steerer is carbon, your friend is SOL.


The star nut was kind of a blunder regarding carbon forks. However, Cannondale was smart enough to produce a unique, integrated alloy top cap sleeve that [partially] doubled also as a compression fitting. The sleeved top cap effectively prevented the carbon steerer from crushing. In 2007, Cannondale did away completely with the star nut on all of their road forks, replacing it with part #KF095...made for Cannondale, by FSA. It is recognizable by the totally flat top and FSA logos. 

As a result, many Cannondale forks from that time period simply have the star nut driven deep down inside the steerer. The best way to fully remove them is to drill the threaded center and shake out all the pieces.

Just because you have never heard of it does not mean it does not exist. I personal have seen some Slice Si forks with star nuts installed, that came that way from Cannondale.


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## Ride-Fly (Mar 27, 2002)

krisdrum said:


> I have NEVER seen a carbon steerer tube fork that calls for a starnut instead of a compression plug or some other set-up (usually a nut epoxied into place). It is worth reaching out to C-dale, but I have a feeling if the fork steerer is carbon, your friend is SOL.


i have heard of one carbon steerer fork (a model of Alpha Q IIRC) that was designed for a star nut.


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## stevesbike (Jun 3, 2002)

Ride-Fly said:


> i have heard of one carbon steerer fork (a model of Alpha Q IIRC) that was designed for a star nut.


these were epoxied into the steerer. I believe Cannondale did too.


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## QuattroCreep (Nov 30, 2009)

Argument over, read through all 4 pages. Your friend should be able to tell if the star nut is ok by reading through this link and seeing if his top cap system matches.

Cannondale Bicycle Corp. 06 EN Cannondale Carbon Road Fork Instructions Tech Note - Free Online Doc

Cannondale, carbon steer tube, star nut, no epoxy.


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## RoadrunnerLXXI (Jun 3, 2012)

krisdrum said:


> I have NEVER seen a carbon steerer tube fork that calls for a starnut instead of a compression plug or some other set-up (usually a nut epoxied into place). It is worth reaching out to C-dale, but I have a feeling if the fork steerer is carbon, your friend is SOL.


I have. When I trimmed down my head steer tube of my Cervelo S2 recently, I discovered there is a star nut installed, but it's inside an aluminum shim with expoxy. Guess that's how the 3T fork which Cervelo used is set up. I winded up pulling out the star nut as well as the shim and replaced with a compression plug. I think the compression plug weights more the the aluminum shim and star nut combined though.

So josephr, tell your friend to double check before making any decision.


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## ericm979 (Jun 26, 2005)

krisdrum said:


> I have NEVER seen a carbon steerer tube fork that calls for a starnut instead of a compression plug or some other set-up


Some carbon forks use star nuts that go in an aluminium sleeve that has been epoxied into the steerer tube.


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## josephr (Jun 17, 2010)

QuattroCreep said:


> Argument over, read through all 4 pages. Your friend should be able to tell if the star nut is ok by reading through this link and seeing if his top cap system matches.
> 
> Cannondale Bicycle Corp. 06 EN Cannondale Carbon Road Fork Instructions Tech Note - Free Online Doc
> 
> Cannondale, carbon steer tube, star nut, no epoxy.




Lots of great information here!!!

Quattro - Thanks so much for the tech document. I forwarded it to him and, I poured thrugh bikepedia and confirmed its a 2006 aluminum and that matches up with this tech document perfectly. I think with the tech document, he can probably get our local C'dale shop to re-install or even move over to a compression fitting. However, he's a little paranoid about a fork failure and has seemingly convinced himself that the only acceptable option is to replace the fork and installing with a compression fitting.

I'm convinced its safe to ride and would be ok to replace the star nut with a $10 FSA compression fitting, but Eddie is the one who has to ride it. I really don't think there's any more information or advice I can give him though.
Joe


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## King Arthur (Nov 13, 2009)

I agree, rudness abounds......


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## krisdrum (Oct 29, 2007)

No argument from me on a nut (starnut or not) epoxied into a steerer. The way the OP described what his friend discovered did NOT sound like that arrangement. If it is epoxied in, no worries, if someone took a standard starnut and just stuck it down in a carbon steerer, installing it like you would on a metal steerer, you likely have an issue on your hands. That is all I was getting at. If there are carbon steerers out there that accept an unsleeved starnut, that would certainly be news to me.


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## josephr (Jun 17, 2010)

krisdrum said:


> No argument from me on a nut (starnut or not) epoxied into a steerer. The way the OP described what his friend discovered did NOT sound like that arrangement. If it is epoxied in, no worries, if someone took a standard starnut and just stuck it down in a carbon steerer, installing it like you would on a metal steerer, you likely have an issue on your hands. That is all I was getting at. If there are carbon steerers out there that accept an unsleeved starnut, that would certainly be news to me.


AS the OP...yeah, that was the diagnosis from Henry was that it was a ghetto repair made by a dumb-ass mechanic. What we've deciphered here is that it was very much designed that way by Cannondale over 7 years ago, before "we" knew that carbon fiber steering tubes and star-nuts didn't make for a good design.

Joe


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## vagabondcyclist (Apr 2, 2011)

krisdrum said:


> No argument from me on a nut (starnut or not) epoxied into a steerer. The way the OP described what his friend discovered did NOT sound like that arrangement. If it is epoxied in, no worries, if someone took a standard starnut and just stuck it down in a carbon steerer, installing it like you would on a metal steerer, you likely have an issue on your hands. That is all I was getting at. If there are carbon steerers out there that accept an unsleeved starnut, that would certainly be news to me.


I agree with the above. 

If the star nut was designed/installed by C-Dale, then it should be ok. I'd still have it removed and replaced with a compression nut based on what we know about star nuts and carbon steerer tubes.


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