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).
Comparing steering ratios and design parameters with Cadillac's system, specifically regarding the La Salle column fitted to the Spectre.
| Identifier | ExFiles\Box 125\1\ scan0127 | |
| Date | 23th November 1934 | |
| X1729 Rm{William Robotham - Chief Engineer} To E.{Mr Elliott - Chief Engineer} Copy to Wor{Arthur Wormald - General Works Manager} Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} By Da.{Bernard Day - Chassis Design}2/MN.23/11/34. Cadillac Steering. Referring to Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}4/KW22.11.34, the comparative absence of joggles on the Cadillac would in addition to the low helix angle, be also helped by the high steering ratio. In the La{L. A. Archer} Salle column fitted to the SpectreCodename for Phantom III the overall steering ratio is still approximately 13.65 : 1, compared with the Cadillac 20 : 1, and it looks as though we cannot do with a higher ratio than say 15.5 : 1. Strictly speaking we ought to reduce our angle below 6° - 35', but the worm is already very large and this would make it larger. As a compromise we are using this 6° - 35' with a ratio of 15.3 : 1. Da.{Bernard Day - Chassis Design} | ||