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I have a bicycle (Göricke, circa. 2012) with an unusual stem. It appears to have a quick-release nut which can rotate through a quarter turn.

Here is a picture, with the dust cap removed:

stem

I would like to shorten the stem, but I can't work out how the system works.

Here is what I tried:

  1. Turned the plastic nut from the 'lock' position to the 'free' position.
  2. Sprayed WD40 down inside the stem.
  3. Unscrewed two the metal nuts 4 complete rotations.
  4. Hit the top of the stem with a soft hammer.
  5. Wiggled the handlebars with the front wheel secured.

The stem is still stuck fast. Does anyone know how to adjust this thing?

Update:

Additional pictures:

enter image description here enter image description here

Update:

The suggested answers were absolutely correct. The bicycle has a quill stem, but the draw bolt was hidden under a plastic plug which I mistook for a rivet. After loosening the bolt, the stem was easily adjusted (no hammer required!).

enter image description here

The plastic quick release nut was a red herring. I'm still not sure what it's for :)

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  • please provide a more complete set of photos showing stem too and any other fasteners
    – Noise
    Commented Aug 1, 2022 at 16:46
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    Any chance the quick release nut puts some sort of limit on how far the bars can be turned? Perhaps to stop front luggage causing wheel to flop around and the rack/luggage bash the frame. Similar idea to the rubber bumpers we see on the top tube of modern MTB's
    – Andy P
    Commented Aug 2, 2022 at 13:26
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    Just a note that since there are presumably ball bearings in thick grease down below the stem, squirting in WD40 may have washed away some of that grease. It may have been a while since the headset bearings were inspected/replaced and re-greased -- now would be an excellent time to do so.
    – Armand
    Commented Aug 2, 2022 at 18:42
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    @AndyP: I think the quick nut is either a parking lockout or damper for the steering. Here’s a similar device, I can’t tell if it’s intended for binary or continuous use: cyclelicio.us/2009/torker-cargo-t-bicycle-headset-lock
    – RLH
    Commented Aug 3, 2022 at 1:01

4 Answers 4

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You loosen the wedge bolt to lower the stem. What's going wrong here is the adjustable part of the stem has been raised to cover the wedge bolt. You need to swing it down using the bolts on the sides and/or underneath the extension, then make your adjustment, then set the adjustable angle back.

enter image description here

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  • Thank you for helping me identify the wedge bolt, which I initially overlooked.
    – onewhaleid
    Commented Aug 2, 2022 at 13:02
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As already mentioned in one of the comments, the quick release is a steering lock. This is helpful when parking the bike while the front basket is loaded. These are also found on 'mom's bicycles' that have a children's seat mounted on the handlebars.

Here's an example: https://www.matrabike.nl/product/3138/liberty-n3

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  • This is probably correct, but the device appears to be broken on this particular bicycle. It's a shame, because it would be much easier to park if the front forks couldn't swing around!
    – onewhaleid
    Commented Aug 6, 2022 at 4:35
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This stem looks like a quill stem. I don't know what the quick release nut is intended for.

Usually if these get stuck, what you want is to loosen the long bolt at the top of the stem (not any of the nuts), so much that the bolt head is clearly above the stem, and then hit the bolt head several times hard with a hammer. It should release the wedge below the stem.

Then you raise or lower the stem (carefully observing the minimum insertion mark), and tighten the bolt at the top of the stem again.

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This is almost a two-part question now. The accepted answer resolves your need of how to adjust the stem's height.

Regarding the quarter-turn lock ring purpose - Is this a folding bike perhaps? It may be a quick release to let you turn the bars and not the wheel, without moving the wedge.

The frame's head tube appears relatively chunky - it may be there's a second "internal head tube" attached to the release ring, and the quill stem is wedged inside that. I'm hypothesising.

Why it doesn't work could be related to rust or corrosion, or it is possible the stem has been changed in the past to your current angle-adjustable style.

I've got one folding bike that has a lever allowing the handlebars to be turned in-line with the front wheel for narrower storage. That this one has a 90 degree turn may be related to handlebar stowage.

You might get some more info by removing the front wheel and looking up the heat tube. It should be blocked completely by the stem's wedge. I'd wonder of there are two concentric cylinders around the edge.

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  • Göricke as a company has been making pedal and motorbikes for over a hundred years. And the top five matches in google images for "Göricke headset lock" are to this question now.
    – Criggie
    Commented Aug 3, 2022 at 10:53

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