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).
Comparison table of specifications for different types of steering gear.
| Identifier | ExFiles\Box 106\3\ scan0285 | |
| Date | 7th January 1935 | |
| -2- Hs{Lord Ernest Hives - Chair}/FJH.{Fred J. Hardy - Chief Dev. Engineer}12/KW.7.1.35. Type of Steering Gear R.R. Marles 15/1 Marles 17.5/1 Marles 20.5/1 Lock to Lock Ratio Stg. Wheel to Road Wheels. 11.9/1 12.8/1 12.2/1 12.95/1 14.3/1 15.3/1 16.5/1 17.7/1 S.S. Tube Movement each way. 0.350 0.250 0.350 - 0.350 0.350 0.350 0.350 S.S. Tube set up Load lbs. 40 40 40 - 40 40 40 40 S.S. Tube Spring Rating lbs/ins. 820 985 820 - 820 820 820 820 Hs{Lord Ernest Hives - Chair}/F.J.Hardy. | ||