You might also want to check out Sheldon Browns tire sizing article as 26" has roughly 4 different bead diameters. Grabbing any 26" labeled tire might be the wrong one for your rims. Kind of a long article but just scroll down a few paragraphs to the "B.S.D." heading for a quick explanation. Explains the ISO (International Standards Organization) sizing which is listed in metric measurements and printed on almost all tires. There are also some charts in the article comparing the different tire sizing systems to ISO. This is the only system that tells you what the actual BSD sizes are if you are in doubt. Tire Sizing Systems