Originally Posted by
Andy_K
I hate to be the one to go all geek but...
I know it's counter-intuitive, but the surface area of the brake pad actually doesn't matter. As you increase the surface area, it distributes the normal force (the pressure of the pad against the rim) and so twice as much surface area leads to half as much force at any given point. This exactly counteracts the increased drag of the larger surface area.
You beat me to it.
It's not just because I work as a hands-on engineer in a technical field, but I often find that the practicality and formalism that one sees in the first two weeks of a high school physics class (and chemistry, for that matter) absolutely dwarf much of the rest of the education that I've gotten in terms of its value.