Originally Posted by
andr0id
Ah, I think you're on to something
Stick a 5mm shim between the pad and rim on each side. Then remove it and see how far the tip of the brake lever moves until the pads touch.
That along with the masking tape behind the cable gets you all three measurements.
You'd still need an accurate way to measure the lever travel. It just gives you a less arbitrary end point. It may still be an improvement.
What I'd really like is to be able to produce a graph of lever travel vs. cable pull for each different lever.