One annoying feature of the chain and sprocket transmission is the chain slapping on the chain stay. Besides being an irritating noise this also wreaks havoc on a paint job. An easy solution is to save the tube from your next flat. If it has a small hole in it, patch it up and use it for later, of course; but if the hole is too big to patch you can recycle it as a as a chain stay protector.
Cut the tube into a piece the length of your bike’s chain stay and split it up the middle length-wise. Clean the tube with solvent and rub with sandpaper to make it easier for the glue to adhere. Wrap the chain stay with the tube, making sure to cover it all the way to the dropout. Stretch the tube around and glue it into place by placing a bead of glue on the outside of the tube and rolling the other side of the tube over the glued portion. This will work best if the seam is on top of the chain stay facing either in or out. Tip: before gluing attach the inside part of the tube with a bit of tape to make it easier to stretch the tube tight. The tube will cover the tape once it’s glued in place.