In 1964, Suntour invented the slant-parallelogram rear derailleur. The parallelogram rear derailleur had gained prominence after Campagnolo's introduction of the "Gran Sport" in 1949, and the slant-parallelogram was an improvement of it that allowed the derailleur to maintain a more constant distance from the sprockets, resulting in easier shifting. The SunTour derailleur cost less than Campagnolo, Huret, Shimano, or Simplex and it performed especially well shifting under load, as when changing to a lower gear while pedaling up a steep incline. A contemporary "Consumer Reports" test reported that "SunTour was far and away the easiest to shift and the most certain of arriving at the right sprocket."