My current tires are 4.10/3.50-6 and I'd like to go bigger. I get confused as to which sizes will fit. Is it any tire that has the same rim size (6, in this case) and will fit the forks and back end? I believe I saw 5.30/4.50-6 on other bikes here. The spread on my forks is 5". Does the 5.30 mean 5.3 inches?