Remove the old carpet or rubber traction plates from the steps with a crow bar. If you plan to reinstall the carpet, take measures not to tear the carpet when removing it.
Wedge the pry bar between the bottom of the original stair tread and the stair riser and separate the two. Do this on both ends of the stair tread. Remove any nails left in the risers with a claw hammer.
Measure from the back of the riser to the front of the riser with a tape measure to obtain your depth. Since the front of the stair tread will have a nose, add 1 inch to the measurement to allow the nose to overhang the riser. Measure the width of the old stair tread with a tape measure.
Cut your new "nosed" stair tread to the measurements you wrote down with a table saw. Remember to cut the back of the stair tread so you do not cut off the rounded nose of the new stair tread.
Drill four evenly spaced pilot holes through the face of the stair tread approximately 1/2-inch away from each end. If your staircase has a riser in the middle, add an additional four pilot holes through the face of the stair tread in the middle. Use a hand drill and a ¼-inch drill bit.
Sand any rough edges with a sanding block or wood file.
Place the stair tread on the risers and position the back of the stair tread against the riser plate.
Secure the stair tread to the risers by driving 2-inch nails through the pilot holes with a hammer.