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Specialized stem installation? Weird design.

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Specialized stem installation? Weird design.

Old 07-26-13, 01:31 PM
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Asi
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Specialized stem installation? Weird design.

So I bought a used bike, with a specialized stem (1"+1/8" threadless system). The weird thing is that I observed a wedge-like gap between the stem and the spacer pressing on the headset (and I had a wedge shim on the top of the stem and the cap screw was flush - thanks to the wedge shim I had) - and realized it's put wrong, and stresses the headset. A big no-no.

After a bit of scathing my head I said.. well I think it was meant to go the other way: wedge part down, so it would be flush on the headset, and so far I've seen this setup in some pictures.
Ok so I'm pretty sure that wedge shim-spacer combo should be at the bottom to make the stem flush with the headset.

Now the problem:

The stem has an oversized hole for that special shim with the wedge shape spacer, and the top of the stem is not flush! but the bottom is flush with the wedge spacer that in terms is flush with the headset.
The top cap that I have does not rest on the stem at all in this setup, The stem has a bigger hole (for that shim) and no lip, and no flat face to rest on even if I had a bigger diameter top cap screw.

So at this moment the headset is pressed against that shim and has nothing to do with the stem.. the stem is resting on the wedge part and the top cap screw is small enough to go trough the stem. So the stem is held only by the 2 side screws of the stem and that's all, and the headset is held separately against that shim. (the shim rises above the top of the steerer tube so the cap screw pressing against that shim is really pressing the headset the right way and flush)

Is this how it's supposed to go? or is there another wedge spacer that goes at top? (or a special top cap screw with a wedge spacer built in?)

This is the exact stem:
Note the inside part is removable and it's the shim-spacer i'm talking about - note the variable thickness of the shim and the variable depth from the stem to the shim - the shim is square but the stem is not square. The bottom part that is less visible in the photo, acts like a spacer of 1-2mm and it is angled to match the stem on the bottom side

Last edited by Asi; 07-26-13 at 01:41 PM.
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Old 07-26-13, 01:42 PM
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That shim can be put in several ways to change the stem angle, but I have never had to adjust one. I can't say for sure if the top cap you have is the original either. Good photos might be helpful.
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Old 07-26-13, 02:30 PM
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Pictures update:

Note: there is no shoulder on the stem itself, and the top cap screw can fall trough the stem but rests on the shim.

So essentially my concern is: is it supposed to be like this? (like.. the stem itself is not held by the top cap screw at all, but only by the stem screws - i.e. I can remove the stem without unloading the headset tension, without removing the top cap screw.)

The cap screw I believe is not original.
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Old 07-26-13, 02:54 PM
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So after a bit of searching I found this: https://cdn.specialized.com/OA_MEDIA/...als/IG0239.pdf

So I miss some parts: the 5mm spacer at top, and the odd shaped "5 star" top cap screw that is eccentric. I bet my starnut is tilted right now using this normal top cap screw.
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Old 07-26-13, 08:45 PM
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I have a few of those stems. The cap is a little bit oversized and it has a lip to seat on the stem. Its bolt hole is also slightly off-center to compensate for the shim, so that the hole can be centered over the star nut.

My stem caps are just a bit different than the ones in the Specialized document you found. They're probably pretty much the same physically, but the markings on them are different. Just a change in cosmetics over time, I'd suppose.
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