I just take a inner tube smaller than the rim I want to protect. Cut it along the inside so you get the smallest diameter. That way it is already one piece, no need for glue or tape. But I have used layers of duct tape and other random things. Also, old inner tubes are great for use on old vehicles when you are replacing the rubber that holds a window into the window sash. You can fold it to whatever thickness you need, and save a lot of money since correct window sash rubber tends to be pretty costly.