Fine tuning V-Brake front shifter cable
Note: This question is not about V-Brake brakes. It is about the combo Shimano V-Brake brand paddle shifters / brake levers.
I have one of these things on my MTB, and I can't figure out a way to fine tune the tension in the front shifter cable. When I am on the middle sprocket in front, the chain rubs against the inside of the shifter cage for my lowest rear gear, which is the gear I spend the most time in. (I'd rather have it rub against the cage when I am in my highest rear gear.)
On other bikes I would put the chain in the middle of the rear sprockets, in the middle sprocket in front, and then fine tune cable tension to center the cage on the chain. Then, fine tune low and high gear with the stop screws on the shifter.
The front shifter has a knurled knob at the seat of the cable, but it has no effect on cable tension. It seems to have had tiny little plastic teeth on it that never worked, and are now wound down to nubbins.
Has anybody been able to adjust these paddle shifters? Or should I just install one of the continuous-movement clamp on down tube shifters I have in my junk box :-) Thanks -w