Any way to run a threadless stem cap on a threaded stem?

What are you trying to achieve? The caps on threadled stems (if even fitted) are normally much smaller than those on threadless, and often angled and/or recessed.

+1 same question. I'm not sure what you're referring to, since stems aren't threaded or threadless, headsets are. The stems are either external for threadless headsets (take a cap) or internal quill type for threaded headsets and there's no place to use a cap.

So do you want a threadless stem using conversion of your threaded Fork & Headset?

I have a Cannondale that came with a FSA stem - I replaced it with a ZIPP. The headset has a threaded internal device that the previous cap had a receptical to screw over and then be able to be drawn down on -the. ZIPP is threadless so there in lies my question and delema

If you had an FSA stem, it was never thread stem, I think the question you have asked is a bit confusing, as its talking about standards incorrectly.

What most people understand when it comes to headsets and associated parts (caps, stems etc) the words 'threaded' and 'threadless' equal two diferent types of headset, which have differnent stem types, whcih are not interchangable, i.e. when describing anything to do with a stemas threaded, you would think quill, for threadless, a-headset.

From your 2nd post, I think that the threaded part you are refering to is actually the fork bung / expander.

Some photos / exact parts you are working with (fork, and stem model) would be useful here.

What model Zipp? Seems like it should have some kind of anchor to cinch a bolt down into. How did you preload the bearings?

wondering if they are parts for a Carbon steerer fork?
a threaded sleeve, that you have to Epoxy in place .


It is a Blind Guess. I recommend Brick and Mortar Bike shops
where people can see what you are talking about ,
since no picture albums are offered or Mfg Product links..

I was going to take some pictures and probe some more and have answered my own question (kind of) I think what I really need to do is change the style of expansion plug for the carbon fork. The current one has a set of threads the cap screws onto and what I need for the ZIPP cap is a expansion plug that accepts a bolt that in turn holds the cap on.

Which leads to a qustion raised from above. If I remove the existing expansion plug do I need to pre-load the headset to put in the new expansion plug? If so how.

I'm thinking you have a star fangled nut in the steerer and a stem cap with a bolt through it to set preload. You are wanting to change from that to an expansion plug type of cap. If the preload is set and the stem tightened, you can remove the stem cap bolt and cap, knock the star fangled nut down far enough in the steerer to make room for the expansion plug and install the expansion plug. No adjustments necessary as, once the stem is clamped down, the cap is mearly decoration.

Careful, you'll put your eye out kid...

But seriously, take it to somebody who understands how a threadless headset is supposed to work because you don't want to be riding along and have the steerer break or your stem to lift off the steerer, a good way to cause a nasty crash. Also, if you ride with the headset loose you'll wear out the bearings quickly or possibly ovalize the headtube on a metal frame which would suck...

Alternatively go to the Park Tool website and read the info there about threadless headset setup and stem installation until you understand it totally before you fix it yourself.

Basically the inside of the steerer tube will have either a star fangled nut or an expansion plug (star nut isn't good for carbon steerers unless there is a metal sleeve glued into the steerer). This sits immobilized in the steerer. Then your dust cap, spacers, and stem (with stem bolts loose) are pushed down by the top cap when you tighten the top cap bolt into the star fangled nut or expansion plug. This sets the headset preload. Then you tighten the stem bolts so it won't move up and down the steerer.

Sounds good - I will make sure not to loosen the stem bolts when changing the plug.

Superglue ??

Star fangled nuts are part of a Threadless headset, fork with a Metal steerer tube..
never use one in a Carbon fiber steerer tube fork.

Seems like you shopped past your mechanical abilities.


You should forget parts on hand, and look for a different expansion plug system.

there are many that expand into the ID of the steerer as step one.

then as a separate thing , there is a second screw to pull down
the top cap, to compress the whole collection underneath it
stem and spacers, with the top bearing race at the bottom of It.

I tie a rope around the fork and the down-tube,
to hold the fork in the frame ,
when the bike is Up on the repair stand.