I've had this on my mind for a while:
Since a small wheel curves downward from the fork crown more sharply than a large wheel it seems to me that the brake pads are not only getting pulled horizontally, but also down. So I'm wondering if brakes for small wheels would be better mounted at a downward angle in order to align the brake bolt with the tangent of the smaller wheel?
Of course this assumes that having the brake forces aligned with the brake bolt like on a larger wheel is a good thing, but perhaps forces perpendicular to the brake bolt (and parallel to the brake arms) actually enhance brake operation? After all I would think there is more flexure in the brake arms than the brake bolt, but the generally poor performance of rim brakes on small wheels makes me skeptical.
What do you guys think?