I always just clamp it directly. If you get your math right cutting the fork, there should be a few millimeters between the bottom of the top cap and the top of the expander plug that's sitting in the fork, so you can get a proper preload, and a nice clean look. However, many people put a small spacer underneath, for two reasons:

1. It's easier. You don't have to be as precise in cutting the fork and can just put a bigger spacer in case you need more space for preloading.
2. Technically, it's safer, as it better aligns the clamping force of the stem with the support given by the expander plug. Without a spacer, the top of the stem is clamping an area that's less supported. However, if you use a torque wrench, you should be fine. I've never actually seen this being an issue in real life.

Okay great, thanks for the answer.

I found the top part of the stem/handlebar combo a bit rough and could not fit a spacer in there properly. Might go for the spacerless option

Hello!

New user here, would like to thank the admin for this forum. A ton of helpful info on here.

I am currently building up a CFR707 with carbonda cockpit and have a couple of questions


(First pic) I am using the provided carbonda headset and i´m wondering if the installation order shown on the picture (red text) would be correct? Or is the spacer above the handlebar unnecessary and should i put the top cap directly on the handlebar?

(Second pic) I also received two metal thin spacers seen on the second picture but don´t know their intended usage, does anyone know?

(Thid pic) Which one of the two provided top caps did you guys use? They seem identical apart from the convex upper part on the one not mounted on the expander.

I have seen some videos on other integrated cockpits and those had alloy shims inside the "stem", where the stem would contact the forktube. I assume my handlebar not having one would be in line with what you all received?

Thanks a lot  in advance and let me know if i should weigh anything or if you guys wonder anything about my build.
Framesize XXL with Rival Etap AXS, will provide final build pictures in this thread