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).
Lower axle ratio for the 20/25 model.
| Identifier | ExFiles\Box 30\1\ Scan133 | |
| Date | 9th March 1935 | |
| -2- Hs{Lord Ernest Hives - Chair}/RM.{William Robotham - Chief Engineer} Wor{Arthur Wormald - General Works Manager}2/R.9.3.35. 20/25. Paragraph 4, page 5 - lower axle ratio. Wor.{Arthur Wormald - General Works Manager} | ||