Originally Posted by
FBinNY
Huh??
Of course they prevent rotation.
No they don't. I used to have notches on the cable adjusters on my brakes. then I got new cable adjusters without them. The cable doesn't move on its own, because no amount of cable force will "push" the adjuster screw into the brake arm. Doesn't even look like Shimano installed them on the earliest Dura Ace RDs. I suppose it's possible, though highly unlikely, that vibration could cause the screw to move...