Width of Stair Runners – is purely a matter of personal taste. There is no convention regarding how wide you runner should be. You might, however, want to consider that a very narrow stair runner, on a particularly wide staircase, may give the visual effect of tightrope walking as you go up & down the stairs. Generally, at least 3″ – 4” of wood showing on both sides of the runner is enough that you will have plenty of area to walk on while keeping the area looking nice.
Stair Rods – are metal rods that are installed at the back of the stair, where the riser meets the tread. The rod is merely decorative and is completely optional. Rods usually have ornamental finials on the ends to accentuate the overall look.
Padding – should be thin so that it doesn’t raise the height of the runner by much. Ideal thickness is 1/4″. It should also be dense, to adequately support the runner so that the carpet doesn’t flex too much when walked on. Rubber pads are a good choice because it is firm & very dense.