Originally Posted by
alexk_il
This is counterintuitive. Can you please explain why moving the arm forward reduces the leverage?
Imagine for a moment that you're hanging from Big Ben by a rope tied to the hour hand. At six the hand is pointing at you and you can't move it no matter how hard you pull. OTOH - at three the hand is horizontal and it's easy to pull it down to 4. Likewise, at five o'clock it's more difficult to pull the hand down to six.
Same with the brake arm. You get the maximum leverage when the cable is meeting the arm at a right angle to it's range of motion. Howver some brakes are designed with variable leverage, offering maximum travel in actuation, and greater force when the shoe nears the end of it's travel range. So my initial statement may not hold true, depending on the internal linkage in the brake, but in any case you get the maximum leverage when moving the arm produces the least pad movement.
Applying this, you might want to shim the entire caliper so the stationary pad is either backed out almost all the way, or cranked in much more. The right answer depends on the specific brake, though the former is more common. You might look at the position of the front stationary pad, since that works well, and duplicate that in the rear by shimming the caliper as needed.
FWIW- and not trying to be snide, there's a difference between hanging a component, and being a mechanic.