Specialized comp multi-stem wedge shaped headset spacer

balances out the angled shim so you can use a normal top cap on your headset
2
9
1
150
updated June 23, 2024

Description

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Motivation

  • Specialized sells a so called “comp multi stem” which includes a shim to further adjust the angle beyond that which the stem is built to
  • while this is fundamentally a good idea, without the special top cap, the fitment of the top leaves a lot to be desired, as shown here
    • this is doubly unfortunate
      • it's easy to lose this special top cap, or if you get just the stem used, the top cap is probably long gone
      • even with the intended top cap, I found that the fitment was still terrible

The headset cap has an angled hole to compliment the tilt of the stem. If you add another 5mm spacer beneath the stem, the level of the top should sit high enough to mate with the headset cap. Once that is in place, you should be all set. 

There are many different shims available:

Solution

  • I once solved this by cutting a spare shim of the same angle to negate the shim under the pinch bolts
    • obviously, you need a spare shim which you might not have

Rev 1

  • STL posted here is for 10 deg
    • change it using the SLDPRT to whatever angle you want
    • unfortunately my real life shim isn't even marked with its angle, so I had to guess by holding it up to a protractor
  • 2024-06-21: don't even bother with this, it was wildly off
    • also too tight on the steerer

Rev 2

  • this worked just fine
  • I found another shim that was marked +8/-16 & used that instead
  • wedge angle copied by measuring the manufactured one; turns out it's 3.38 deg for a +8/-16 deg shim
    • too lazy to figure out the geometry on this one

Explanation of angles:

10 position angle range, 2-degree increments: [12-degree] +/- 8-degree to 16-degree, [17-degree] +/- 13-degree to 21-degree, [24-degree] +/- 20-degree to 28-degree

  • this seems to suggest that a stem bought with a built-in 12 deg angle would come with a shim that can make the resulting angle +8 or -16 deg, meaning the shim itself produces a 4 deg change either way
  • this would make sense given that my 3.38 deg spacer ended up working acceptably well
  • this is sort of weird because I think the shims being labeled +8/-16 is misleading since that depends on what stem they're paired with – unless such a shim is only compatible with a 12 deg stem
    • that's possible, but sounds somewhat stupid
    • maybe Specialized had a good reason for such a nuance

Rev 3

Added second indicator notch to make it easier to line up the wedge.

 

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