SystemSix carbon fork with starnut

Discuss light weight issues concerning road bikes & parts.
martinko
Posts: 359
Joined: Fri Dec 06, 2013 9:08 am
Location: Slovakia

by martinko

Seen and read much praise about SystemSix frames here. And then, quite unexpectedly, I managed to get one locally, cheaply. The painting is in clean condition, just minor chips near the BB bearings. It’s a stunning ride, thanks for introducing me to SystemSix :)

It’s problably a 2007 model, see crappy photo, please. Proper photo after the build is finished :)

It came with starnut installed in the (carbon) fork steerer. From what I read about first SystemSix frames and how it looks, it was like that from the factory.

But there’s a little problem, maybe. The starnut is pushed too much down in the fork. It’s just under the stem and the top cap bolt is screwed about 1cm in it (dark part of the thread on the bolt).
I can still tighten the headset well, there is no problem. I am just worried whether any problem may surface from riding this.

So, I thought about leaving the starnut there (not WW solution, but safety first) and use the KP017 compression plug from my previous CAAD10. However, that would not fit in, the starnut is not that much inside for that.

I don’t want to pull the starnut out of the steerer, as it may destroy the steerer. If I had to use the compression plug, I thought about pushing the starnut further down to make space for the compression plug. But, would it not damage the steerer as well? Do I have to worry about it or just use it like it is? Unfortunately, I don’t need to lower my stack for now, so I ignore option of cutting the fork and getting nearer the starnut.

Many questions, here I summarize:
- Is it correct that SystemSix frame came with starnut installed in the carbon fork steerer?
- Is the starnut pushed too much down and should be a bit higher?
- Headset is still tight, so, ride it like it is? For now I do.
- Push it further down and use the compression plug instead?
- Source a new SystemSix fork, hope for no starnut inside, and just use the compression plug?

Current setup of the headset spacers is: two SystemSix carbon and aluminium cone spacers (30mm stack), Deda SuperZero stem (35mm stack), 5mm spacer to make room for tightening (because of the stem having not the standard 40mm stack).

Thanks!
Attachments
systemsix.jpg
current stack.jpg
starnut.jpg
top cap bolt.jpg
top cap bolt side.jpg
compression plug try.jpg

alcatraz
Posts: 724
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

What is that starnut made of I wonder?

Can the steerer really be damaged by pulling it out with some sort of extractor?

Also there are shorter compression plugs available that might do the trick.

Running a starnut in a carbon steerer, is this effectively the same as running without a compression plug? I used to do that but I got annoyed with everyone warning me about it so I got a cheap lightweight one in and I can't tell the difference really.

/a

by Weenie


sussexhills
Posts: 52
Joined: Fri Nov 18, 2016 10:31 am

by sussexhills

The normal advice is to not attempt to remove the starnut but to push it further down the steerer and install another, obviously this depends on how much space you have. However for a carbon fork I'd not be using a starnut anyway and would go with a compression plug. I'd go with the new Cannondale low profile one that relies on the topcap plastic assembly providing structural support for the stem clamp area with only a small expanding wedge underneath - it's Cannondale part number KP017. Hope this helps.

allenpg
Posts: 112
Joined: Tue May 20, 2008 5:34 am

by allenpg

alcatraz wrote:Can the steerer really be damaged by pulling it out with some sort of extractor?


You can simply drill the starnut out...just don't hit the carbon...;)

I've done this several times on MTB forks when switching them between frames. I used a drill bit that was a bigger in diameter than the threaded hole.

jobvisser
Posts: 78
Joined: Sun Aug 14, 2016 10:24 am

by jobvisser

allenpg wrote:
alcatraz wrote:Can the steerer really be damaged by pulling it out with some sort of extractor?


You can simply drill the starnut out...just don't hit the carbon...;)

I've done this several times on MTB forks when switching them between frames. I used a drill bit that was a bigger in diameter than the threaded hole.

just drill it out or get a longer bolt :P

C36
Posts: 189
Joined: Fri Mar 03, 2017 3:24 am

by C36

allenpg wrote:
alcatraz wrote:Can the steerer really be damaged by pulling it out with some sort of extractor?


You can simply drill the starnut out...just don't hit the carbon...;)

I've done this several times on MTB forks when switching them between frames. I used a drill bit that was a bigger in diameter than the threaded hole.

Would do with a lot of care, a friend attempted it on a Slice fork and, probably due to too much force applied, the starnut started spinning and cut fibers :(


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ipaul
Posts: 157
Joined: Mon May 30, 2005 2:06 am

by ipaul

Cannondale SystemSix forks used a starnut when sold. Even listed in the instructions. I say just keep using it as installed.
:P

topflightpro
Posts: 800
Joined: Tue Jan 13, 2009 2:35 am

by topflightpro

ipaul wrote:Cannondale SystemSix forks used a starnut when sold. Even listed in the instructions. I say just keep using it as installed.


Funny, mine didn't come with a starnut. It came with a compression plug.

And my Six-13 before that, with the Premium+ fork, also came with a compression plug.

And OP, is the inside of your headset cap threaded?

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bikerjulio
Posts: 1901
Joined: Fri Dec 11, 2009 10:38 pm
Location: Welland, Ontario

by bikerjulio

I would have bet Cannondale never used a star nut in a carbon fork, and then I found the users manual for the System6. There is also Cannondale's long top cap inserted over this which supports the steerer against crushing from the stem.

Cannondale want the top cap to be fully inserted with no spacer above the stem. So the steerer needs to be cut 2 mm below the final stem location top. Then the star nut set 40 mm down from that.

I'd also suggest that the original unique stem and spacer combo does a better job of supporting the steerer, and that if one can be found, it not only looks better, but is stronger.

Image

Image

http://cf-prd.cannondale.com/~/media/Files/PDF/Dorel/Cannondale/Common/Support/ROAD%20OWNER%20MANUALS/SYSTEM%206/2006_system6_owners_manual_supplement_en.ashx?vs=1&d=20150812T065500Z
There's sometimes a buggy.
How many drivers does a buggy have?

One.

So let's just say I'm drivin' this buggy...
and if you fix your attitude you can ride along with me.

http://www.youtube.com/watch?v=GekiIMh4ZkM

martinko
Posts: 359
Joined: Fri Dec 06, 2013 9:08 am
Location: Slovakia

by martinko

Thanks everyone for your input.

@alcatraz, the starnut is made of steel I assume. It has been normally used for alluminium steerers, but not for carbon, since it eats into the steerer walls and so it may damage the carbon structure.

@sussexhills, is there any way to find out how much further I can push it down? I would assume that there is as much space as the fork steerer is long up to the crown race. But my LBS mechanic refused to risk it to push it down anyway to not damage the carbon walls (can check other courage of other LBS mechanic later, of course).

@allenpg, @jobviser, did you also have got it in forks with carbon steerer? Like @C36 mentioned, I am affraid I would damage the steerer when drilling it out.

@topflightpro, no threads on the headset cap, its just hollow barrel with top cap which holds the bolt. I think it is original top cap for this fork since the top cap has "SI System Integrated" logo.

@bikerjulio, thanks very much for pointing out the SystemSix manual: download here. On the page 7 they show the starnut should be installed in 40mm depth. I measured the depth of mine and it is exactly 40mm inside. So that seems to be ok and I should not have to worry about anything, I think now.


I created simple illustration how it looks when assembled (crappy, I know, don't have better tools for that now). And I think I have got the starnut inserted in proper depth (40mm).

From the beginning, I have not got much experience with starnuts - have one on my very first road bike and never touched it since bought, but the top cap was different and the starnut was on the level of the stem.
In this case, I was worried if it is in the right place, or else it is too much pushed down the steerer. Based on the original SystemSix manual, it seems to be ok. The top cap bolt provides support for the steerer walls (see photo no. 4 "top cap bolt side" for the profile view).

So, it should be ok, I hope. I am absolutely fine with riding with starnut inside if it still considered safe. I will try to reach Cannondale to double-check as well.
Attachments
current stack illustration.png
current stack illustration.png (3.84 KiB) Viewed 1291 times

allenpg
Posts: 112
Joined: Tue May 20, 2008 5:34 am

by allenpg

C36 wrote:
allenpg wrote:
alcatraz wrote:Can the steerer really be damaged by pulling it out with some sort of extractor?


You can simply drill the starnut out...just don't hit the carbon...;)

I've done this several times on MTB forks when switching them between frames. I used a drill bit that was a bigger in diameter than the threaded hole.

Would do with a lot of care, a friend attempted it on a Slice fork and, probably due to too much force applied, the starnut started spinning and cut fibers :(


Really good point. The adhesive force between aluminum vs carbon is going to be different. I was thinking more about the bit hitting the carbon...forgot that it might spin.

If tried it and it started spinning, I would go the Dremel route with a small cutting tool. Might take longer, but also more precise.

bremerradkurier
Posts: 234
Joined: Mon Jun 13, 2016 4:18 pm

by bremerradkurier

You might be able to get a longer electric jigsaw blade into the starnut threads, notch it in several places until the petals lose support and you can drop them out.

sussexhills
Posts: 52
Joined: Fri Nov 18, 2016 10:31 am

by sussexhills

What happened with this @allenpg?


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Nixster
Posts: 41
Joined: Wed Oct 04, 2017 3:30 pm

by Nixster

Am I missing something here? It seems you have two options: either continue using the star nut and matching top cap or remove the star nut and use the likely much lighter current part. Just don't mix and match! Personally I don't see that pushing the star nut further down would be an issue, after all that's how it got there in the first place. Pulling it out on the other hand doesn't sound like a great idea, nor does drilling it not least because you could end up with a useless star nut stuck down your steerer.


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by Weenie


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shoemakerpom2010
Posts: 251
Joined: Mon Apr 11, 2011 6:28 pm
Location: Palm Coast, Fl.

by shoemakerpom2010

That's not a starnut its the bottom of the FSA compression plug stuck in the fork. Your going to have to remove the stem and spray some lube in there to loosen it out (its probably seized over time if its not removed regularly, This happen to me on mine). Once out throw out that crappy compression nut and buy this and all problems go away....
http://www.cannondaleexperts.com/Cannon ... p_106.html

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