A lot of tire sellers have handy charts on their sites or in catalogs showing tire sizes and/or rim sizes and what will fit.
The antique tire suppliers like Coker Tire and Diamonback Tires (
www.dbtires.com ) can convert the bias ply sizes to their modern equivalents.
If the tires are still on your rims, write down the size and look them up or call Coker or Diamondback.
