Remove the old straps by cutting them in the middle with scissors. Pull out the straps from the metal frame.
Clean the chair's frame with a rag and mild detergent.
Measure the length of the new vinyl straps with a cloth tape measure. Use the cloth tape measure to mimic the way the vinyl strap would wrap around the frame to get an exact measurement. Then take the measurement, multiply it by .85, and add 1 inch. The resulting measurement will be used to cut new straps. The measurement is reduced because the vinyl straps are designed to expand when heated.
Cut new sections of vinyl straps using the measurement from step 3.
Drill a hole 1/2 inch from the ends of the straps using a 3/16 drill bit. Cut 45-degree corners on the ends for easier insertion into the frame.
Boil a pot of water, and let the vinyl straps soak in it for 5 minutes. Remove with tongs. The straps are now ready for stretching.
Attach plastic rivets into holes at the ends of the straps, and insert them into the frame. Wrap the straps around the frame. An extra pair of hands may be needed to assist in stretching out the straps into place.