I recently purchased a new Roubaix that comes with the comp 12 degree multi stem. The stem is horizontal now but I'm trying to get a bit more stretched out on it.

I've been trying to understand this guide from specialized (https://service.specialized.com/collateral/ownersguide/new/assets/pdf/Stem---Carbon-Road-Stem-Instruction-Guide.pdf)where apparently you can add or remove shims to adjust the stem angle. My stem didn't come with any additional shims.

I'm a bit confused and need a laymans explanation about whether I can extend this stem by removing shims or perhaps flip it to extend reach (its horizontal now)

Thanks for the help!

It seems like you wish the extension length be shorter It seems obvious from looking at this PDF you listed

:>https://service.specialized.com/colla...tion-Guide.pdf

that it is Just an angle adjustment, and much less than other angle adjustable stems But....

extension reduction means Buying a shorter stem.

Why dont you go back to the Dealer and talk about making the bike fit better.. ?

Thanks for the quick reply. What do the stem shims in the PDF do/ refer to?

is not it obvious?

No or else why would I ask. I'm not as experienced as you sovI appreciate your advice. I know what a spacer is but shim I'm not familiar with.

Looks like tapered shims, that fits between the steerer tube and the stem.
It changes the up/down angle of the stem. Gives a bit more flexibility in finding a comfortable setting for you, without having to use a different stem.

With a "regular" stem, you have 2 choices by flipping the stem over ... A or B
With shims you multiply the options, as shown by the red & blue lines.

Thanks for helping me out. Are the shims in between the steerer tube and I can remove them to adjust the angle or how would I go about removing them to adjust?

Note: My bike did not come with any shims that I know of.

I love those adjustable stems! Specialized really came up with a good idea on that one.


Basically, look at your stem where it mounts to the headtube; there's an oval "window" and there should be two numbers visible through it (numbers that are stamped into the shim). Those are the degrees that you can raise and lower the stem. Now look on the both sides of the stem next to the oval window, there is an arrow on one side (it's a triangle); that is where you put the degree of angle that you want. The best way that I can describe it is if you want 12* of rise, look for the arrow on the stem, slip the shim in so that the 12 is next to the arrow, this means that you will be working with 12*.


Now, depending on whether you mount the stem slanting up-or-down, you will have 12 degrees of either rise or drop. I don't know what the other value is on your shim but the same rule applies: if it's something like 6*, put the six on the side of the arrow (doesn't matter if it looks upside-down or right-side up) and you are now working with 6*.


Does that make sense?

Normally, a shim is equally thick all over. These - if you were to cut one up and look at the face of the cut - would be wedge shaped. Depending on how you orient the shim - pointy end up or down - will give you a slight change of angle to the stem.

Hold it in your hand.. I dont have one . so let's guess.. it is made so it can change the angle.. because

unlike most stem to steerer tube shims its not one consistent wall thickness , Like I'd use with a 1" to 1 1/8" adaptation.
shim is a sleeve a tube of a thickness like 1/8" is a diameter difference between 1" & 9/8"..

Since you seem to want a shorter extension stem Go back to the shop you bought the bike from

and buy a different stem, this time get one that is not so confusingly complicated by its angle Adjustability.

Dealer should give you trade in value for the original stem .. and spend time with getting the fit more satisfactory .

I get the sense you bought a more sophisticated bike than your mechanical abilities can cope with..

Do rely on the Dealer, primarily for help as We cannot do that for You ..


I recommend reading Books on bike repair mechanics and reading several ..

I'm not familiar with the product, but my GUESS, is that a special oversized stem can be purchased, that comes with the various shims listed. You experiment with the different options, which moves the handlebars up & down a bit, until you find a setting you like.
If your bike came with the adjustable stem, then I assume you got a set of shims also ?? I would assume the 0 degree shim is installed, with the others available if you prefer.

Then you need a longer stem. An adjustable stem won't help you.

Just go and look at the bottom of the stem. Better yet, take the stem off and it will all make sense. It's more a spacer than a shim. The bottom (which the stem sits on) has an offset cut. So in one position it will angle the stem up 2*, etc. And if you turn it 180* it will angle it down by 2*, etc.

But like homebrew says, if you want to be more stretched out (ie. longitudinally) rather than more drop, you need a longer stem.

You need a different stem if you want to change reach.