From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Table of tyre and rim specifications with corresponding inflation diameter, inflation width, and effective radius dimensions.
| Identifier | ExFiles\Box 45\2\ Scan360 | |
| Date | 8th October 1931 | |
| MESSRS. ROLLS ROYCE LIMITED. 8.10.31. Tyre Size & Type. Rim. Infl.dia. Infl.width. Effec.radius. 7.00-21 Standard. 5x21 34.95 6.67 16.3 4.00x21 34.83 6.85 16.3 7.00-21 Fort. 5x21 35.44 7.06 16.5 4.00x21 35.38 7.22 16.5 7.00-20 " 5x20 34.44 7.06 16.0 4.00x20 34.38 7.22 16.0 6.00-20 " 4½x20 32.93 6.18 15.44 3.62x20 32.85 6.41 15.44 6.00-19 " 4½x19 31.83 6.24 14.94 3.62x19 31.75 6.47 14.94 5.25-21 " 4x21 32.42 5.50 15.31 3.25x21 32.37 5.80 15.31 4.40-19 " 3½x19 28.69 4.55 13.63 2.50x19 28.65 4.65 13.63 | ||