Hy Chetman, in most cases you want to loosen the tire bead, and push it towards the center of the wheel, this can be a very hard job. It's amazing how rubber can weld to steel, especially if given half a century for the process to complete itself. Once the bead is loosened you can push the outer portion of the wheel towards the center of the wheel, to allow the lock ring to be pried out of its groove [depending on the make and design of the wheel]. There are heavy hammers where one side of the head has a large flattened area to assist in breaking the bead, this is very hard work, be careful and wear safety glasses and steel toed boots, good luck.
