Originally Posted by Diode100
There was a grove in the handlebar stem, but no key in the post, so the stem rotatated freely. Probably I needed to use the micro scew to get a rough fit before trying to set the bars, but my feeling was that that the tolerances on the set up were far too large and however effective the clamp there is always going to be a tendency for the bars to rock in the post.
On my Curve, there are actually a couple of little bumps inside the handlepost which do catch that groove. They are much smaller than the groove, so the stem could rotate quite a bit, but not all the way. It wouldn't be possible to fit a stem without that groove.