Originally Posted by jwa
What he said.
I needed to cut away part of the plastic which mounts on the brake hoods to allow full motion of the brake levers. Nevertheless, the mirror is real stable.
I have found the hinge joint which allows mirror adjustment tends to be the weak design link - I've replaced mine every 2 years or so due to breakage here.
The weak link to these mirrors for me was breakage if your bike fell over. I broke and repaired my mirror several times before it could not be repaired again. This was on tour and you should have seen the knot of duct tape holding the thing together!
The B&M cyclestar will just bump out of the way when dropped, it does not break.