I mounted mine on the bar as well. I thought the stem was a lousy place to get a view at the LCD screen. On the bar you can fiddle with the angle so the screen shows up the best for your position. On top of the handlebar tape, the mount snugged down just fine, no vibration. I also used some old tire tube around the chainstay so that the cadence / rear wheel sensor could snug down real tight, and prevent the rear wheel sensor from drifting into the spokes and self destructing.