I had trouble at first too but I had to just tighten the two Allen bolts down really tight (as tight as I could possibly get them) and so far it hasn't move since. But I did it a specific way: When first assembling the stem onto my bike/bars I made sure to loosely tighten both Allen keys the same amount. Then I just went back and forth between them tightening each one a little at a time (always the same amount so that they got tightened equally). Once the Allen bolts start getting hard to turn I made sure to only tighten a little bit, like a 1/4 turn at most, then repeat on the other one. Kept doing this where I made sure I was always tightening each one the same amount, back and forth until I couldn't turn them at all anymore. Hasn't moved since.I also made sure that the fork stem, bar clamp stem area and all inside surfaces of the stem were very clean with simple green, so no grease or anything. Didnt sand anything, original paint is still on all parts, etc. My fork is an odyssey f-zero and my bars are WeBicycles Gov. Both are still relatively new, no ovalizing or anything yet on fork stem.For what it's worth I haven't watched this Pete Brandt video so I have no idea what his advice was. I'm gonna go watch it incase I should be doing something different.I've also considered using a different tool so that I can tighten them down even more if needed but so far haven't had the need. Currently just using a regular ole Allen key. Was thinking of one of these two tools, would just have to be careful not to over tighten:
Decided to keep for a future build. The top half of the stem sits about 50 percent over the top of the steering tube, so no room for adjustment.