I have a new Roubaix Comp with the adjustable stem. I see how to adjust the angle. My question is dropping it lower on the steerer tube. If I pull off one spacer to lower the stem, does that spacer have to go back on the top of the stem ( under the top cap)? It seem as though it does't need to.
Also, what is the proper procedure for tightening everything back up?

Thanks

You either need to move the spacer above the stem or remove the spacer and cut the stem. Otherwise you will have a lot of play in the headset.

It should go back on the steerer above the stem and under the cap.

Ok.....Thanks
That's what I thought but when I put it back together without the spacer on top it seemed ok, i.e. the steerer tube wasn't really sticking up above the top of the stem.
Do I tighten the top cap slightly, then tighten the stem bolts or tighten the stem bolts tight first, then the top cap bolt?

You need to learn how to do a threadless headset adjustment. The top cap bolt is not a simply turn until proper torque. That bolt is the headset adjustment. The stem bolts are not tightened until this adjustment is correct. You will also note that top cap is orientation specific - know what you're doing.

Good advice ... why not post a how-to on headset adjustment?

Better, yet, let the pros at Park do it. See this page: https://www.parktool.com/repair/readhowto.asp?id=65

Does this work with the Comp-Set stems? I've seen opinions to the effect that because of the offset induced by the shim, that the stem cap must go directly above the stem. That kind of makes sense, in that the offset would be different if the spacer was between the cap and the stem increasing the vertical distance. But in that case, why do the bikes come with a full spacer stack below the stem? Does that mean if I want to change the vertical height as well as the angle, I would need to cut the steering tube down by the width of the spacer I remove, rather than just shift it above the stem? Seems awkward in a system that's designed to be reconfigurable.

KeS

(yes, I know this is an old thread, but it's still germane information; didn't see the point in starting a new one)

It doesn't really work well. I don't think anything's going to fall off, but it looks terrible and it probably isn't distributing the load evenly. The bikes come with all those spacers because you can always remove spacers and cut the steer tube down, while you can't add steer tube unless you buy a new fork. Unfortunately, threadless is not as easily adjustable as the older quill system.

Thanks. Ended up needing a shorter stem anyway, so bought a new one from the dealer, and the instructions there say that it is not recommended to run a spacer above the stem/shim "for extended periods" on bikes with carbon steerers. Not really clear still if that's an issue of the angle shim, or just stem configuration in general.

The dealer said the spacer stack is there in case an owner wants to go to a standard non-adjustable stem, which makes sense.

Appreciate the response.

KeS