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Discussion Starter · #1 ·
I have just brought some Marzocci Z1 ETA 150mm suspension, the seller said.

"The steerer has 180mm left to keep the front end nice and low. If you're unsure if this is enough, the headtube on my bike was 4", and I was running 3 10mm spacers with my stem on top. Disc mounts are IS. There is a star nut fitted. Steerer is 1 1/8". 20mm bolt through axle."

What is the purpose of the Star Nut? And will I have to remove it to fit my forks to a Kona Scab frame?
 

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The star nut simply "pulls" everything together (fork, stem, spacers, headset) on top so there's no play or movement. Then you can secure it tightly using the stem's bolts. Once the stem is secured the starnut doesn't really serve any purpose other than holding the top cap of the steerer tube in place.

You can re-use the starnut when you put the fork on your frame. You can just add spacers on top of the stem if it's longer than what you need.
 

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The star fangled nut does not need to be removed - you can use it as-is.

The sfn is lodged (hammered in) inside the steer tube approx 10mm or less below the top. A bolt is then screwed into the sfn from the top to secure the top cap with the stem and spacers rings (if any) below it.

Basically, this arrangement tightens the bearing contact within the headset and stops the fork from falling off the frame.

This setup is used only on ahead style (ie not threaded) forks - which is the current norm.

If you need to install a new sfn (say, because your top cap bolt is threaded differently), you can hammer (using an iron rod or pipe etc) the old one slightly further down the steerer tube and just hammer in the new one just above it. Alternatively, you could just drill the old one out.
 

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As others have said, the star nut is for the top cap bolt. It's important to know that this is for adjusting only and holding the system together until the stem is tightened to the fork.

In ready to ride condition the stem clamp bolts hold it together, not the top cap bolt. If you want to re-adjust the headset you have to loosen the stem clamp first.

You probably knew this, but many don't, and folks trying to adjust headsets by forcing the top cap bolt is probably the number one cause of problems in these systems.
 

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local trails rider
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Your link leads to some axles and axle parts, not hubs.

Is your Z1 for a 20 mm axle? Forks for 20 mm axles seem to come with the axles.
 

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Noobie
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I would recommend looking on ebay for a complete wheel with a 20mm hub (where I got mine). This is a buy-it-now I found, and I see no problems with it.

EDIT: Realised I assumed you were UK. There's quite a few buy-it-now 20mm wheels on ebay.com actually, kinda spoilt for choice.
 

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local trails rider
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Chainreaction builds pretty decent wheels too, at very reasonable prices.
 
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