From the days when I played with bikes and their brakes, I understand that the pad should bit on most, but not all, of the surface of the disc, about 2/3mm unused each side.
The pad should never, ever, extend above the edge of the disc.
That sounds like excellent practice of course but just in case people get worried about this from looking at their own, page 162 of Dave W’s book refers to Caparo callipers causing a ridge of unworn pad material build up on the outer edges, which needs to be regularly chamfered back! When I read that, I immediately checked my own, and it was certainly true for mine.
Yet another Morgan “thing”.
