Thanks for the tip Mengy! SuperView sounds like a good idea for my Hero 8 on the handlebars.
FWIW, I recently got a Hero 9 and I put that on my helmet and then used the Jaws clamp mount to put the 8 on my bars. I can't fit something like a Large Bar Mount (which I have and tried) on the handlebars. The smaller mount by GoPro is too small, the Large one is too big and would pinch wires, but the Jaws clamp fits right in, doesn't pinch anything, and then has the gooseneck on it to get the 8 positioned well. I think the footage looks good, but I need to change to SuperView for an even better rider-view angle!
The Jaws clamp does occasionally move a bit, so I may try reversing it to put the weight where it won't rotate, but generally it's really nice, and the 8 does a great job at stabilization (in one of my early tests I put the Jaws mount right on my left grip... it was only mildly distracting and dangerous LOL - I only left it on for 5-10 mins).
I also used a RickRak 360 mount and put the small bar mount on one of its positioning screws and then mounted the gopro on the gooseneck on that... that was interesting. With my mic cord dangling, once I hit 35mph or so it was flapping in the wind and wildly distracting. I literally pulled over like 2 minutes later and took it all down.
-John