I'm running a 1.5" Pig FSA headset, 1.5" Totem, and a 1.5" Thomson 4x stem, and three 5mm interlocking spacers (one below the stem, two on top).
After nearly every run down the mountain there is a little play in the headset.
Yes, I crank down the top cap before tightening the stem bolts. Yes, there is a gap between the top cap and the stem (actually headset spacer that I'm running on top)....What I'm I missing?
I'm gonna pull the headset apart later, but everything was installed correctly.
An ovalized headtube doesn't seem possible yet, but I'll measure it with a pair of calipers.