>>2012623canti are fiddly to set up initially. the little cable(s) between the arms have to be a certain length/angle depending on which model arms you have. Shimano manuals explain it and they even made special plastic bits that laid along the cable for the specific brakes but I figured it out with some cardboard .
but once you set it up it's good forever. they'll still work if you guess at it, but for optimum performance you do that.
