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Hello All,

I'm after a bit of advice.  I have a Cube Attain GTC, which has carbon forks with an alu steerer tube.  When I try to tighten the compression bung (FSA) it won't grip totally, so when I tighten the top cap it slips and I can't compress enough.  Any tips of how to sort this or should I just buy a  different  bung?

Cheers, Lee

7 comments

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srchar [1324 posts] 3 weeks ago
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If the steerer tube is alu, you can use a star fangled nut.

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ktache [1488 posts] 3 weeks ago
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Maybe give everything a good clean so you have metal on metal.  Once the stem is tightened you can remove the bung and lube a bit.  the top cap shouldn't be too tight in use anyway?

When I got my first Aheadset it was an FSA, I liked that it wasn't a star fangled nut, they scare me a bit.  I am at this moment servicing my Chris King No Threadset, Not going anywhere near the star fangled.   Bit annoyed that I have to clean and lube the bearings whilst in the frame, but my god it's a work of engineering art in there.  Left it a bit long, 8 years, I think, greased externally when servicing forks (Marzochi Z2s 98, plush as) , but it's still clean in there and shiny.

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leelang229 [14 posts] 3 weeks ago
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Thanks guys,

Not sure I want to go the star nut route, it looks a bit difficult to get the nut inserted and at the right level without a proper tool.  I think I will have a go cleaning everything out, and maybe get a new bung if thhat dooesnt work.

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srchar [1324 posts] 3 weeks ago
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A mallet, a screwdriver, and some care are all you need!

If you're going to get a new bung, get a longer one, so you'll have more contact area between bung and steerer.

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Drinfinity [182 posts] 3 weeks ago
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I usually bash a star nut in with an old headset bolt in it. Once it is started, you can keep tapping it straight.

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leelang229 [14 posts] 3 weeks ago
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Thanks for the advice chaps.  I greased the inside of the expansion plates (and the bevelled faces of the top and botton bolts), so they slid apart more evenly when I tightened the bolt ; it worked an absolute treat!  I can nip everything together tight enough now to stop any play when braking.  Sometimes it's the easy fixes that work best!!

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ktache [1488 posts] 3 weeks ago
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Oddly, after doing a full sevice on my Chris King and my Marzochi Z2s (98?) I had slipage on my star fangled nut, managed to get enough traction to nip up the stem adequetly, but back to the LBS for their tools on this one.  Wonderful shakedown ride this afternoon, turned into a really nice evening, found myself in a bluebell wood.