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 vehicle speeds in MPH and corresponding gear ratio calculations for different bevel settings.
| Identifier | ExFiles\Box 4\8\ 08-page06 | |
| Date | 20th May 1913 guessed | |
| X469 c SPEEDS IN M.P.H. ENGINE REVS = 1000 TYRE DIA = 895 m/m BEVELS RATIO REVERSE 1ST SPEED 2ND SPEED 3RD SPEED 16-52 3.25 8.46 10.55 17.82 28.85 17-52 3.06 8.98 11.22 19.08 31.71 18-52 2.89 9.52 11.87 20.17 33.58 GEAR RATIOS REVERSE 1ST SPEED 2ND SPEED 3RD SPEED. 50/30 x 44/21 50/30 x 46/26 50/30 = 35/35 EQUAL 3.49-1 2.82-1 1.66-1 1.-1 | ||