The part of the rim where the brake pads actually press, is unusual: Where most wheel rim surfaces are shiny and smooth, this rim has very thin groove running circumferentially. [...] I don't know if this will accelerate brake wear or not - the grooves run in the direction the wheel in spinning, so one would think they would simply carve tiny grooves in the brake pads themselves.
These tiny grooves actually improve the braking effect (ever so slightly). It's used to increase the "swept area" of the brake contact surface.
