Today, I ran across this website that gives a lot of good information about tire sizes that were used in the past, and what the modern replacement size would be. Click here...
From the website.....
From the website.....
[FONT=Arial, Helvetica]The chart below is for conversion of one type of size series with original inch sizes from the 60's and 70's. This is for as close to a direct replacement for each size but is not endorsed by any safety group or manufacturer of tires or automobiles. You should always use the proper size tire but when an older car size is no longer produced, this might help. Please consult your tire dealer before you make any decisions if you are in doubt as to if you should use a certain size tire.[/FONT]