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).
Gearbox ratio data for the Standard Phantom II.
| Identifier | ExFiles\Box 15\5\ Scan236 | |
| Date | 23th January 1914 guessed | |
| X7310. (1) STANDARD P.II BOX. Revs of Prop Shaft per rev :: of engine 4th Speed. | 3rd Speed. | 2nd. Speed. | 1st Speed. | Reverse. Direct. | .735 | .500 | .285 | .324 Revs of engine per rev of 3rd motion shaft. 4th Speed. | 3rd Speed. | 2nd Speed. | 1st Speed. | Reverse. Direct | 1.3608 | 1.9984 | 3.5117 | 3.0864 Revs of engine per rev of road wheel. (11/41 axle) 4th Speed. | 3rd Speed. | 2nd Speed. | 1st Speed. | Reverse. 13.727 | 5.065 | 7.454 | 13.4 | 11.5 | ||