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 steering specifications for different Phantom series.
| Identifier | ExFiles\Box 17\3\ Scan203 | |
| Date | 23th March 1928 guessed | |
| COMPARISON OF STEERING PHANTOM SERIES | 'V' | CONVERS | 'B' 2 | 'F' 2 | 14 EX E.A.C. 7 | SPORTS CAR WITH SHORT PEND LEVER F'2 CONV. | EXP LEAD | 1.125 | .940 | .720 | .720 | .720 | .720 | .900 PITCH DIA | 1.400 | 1.400 | 1.800 | 1.800 | 1.800 | 1.800 | 2.150 HELIX ANGLE | 14°-20' | 12°-4' | 7°-15'-17' | 7°-15'-17' | 7°-15'-17' | 7°-15'-17' | COEFF OF FRICTION .133 7°-35'-23' Nº OF STARTS | 4 | 4 | 3 | 3 | 3 | 3 | 3 ANGLE OF CUTTER | 29° | 29° | 29° | 29° | 29° | 29° | 29° ROCKING LEVER | 2.300 | 2.300 | 1.750 | 1.750 | 1.500 | 1.750 | 2.000 PENDULUM LEVER | 9.500 | 9.500 | 9.500 | 11.000 | 7.500 | 9.500 | 10.000 SIDE STEERING LEVER | 8.000 | 8.000 | 8.000 | 9.225 | 9.500 | 9.225 | 9.225 LOCK ANGLES | L.H. 38° R.H. 32° | L.H. 38° R.H. 32° | L.H. 38° R.H. 32° | L.H. 38° R.H. 32° | L.H. 38° R.H. 32° | L.H. 38° R.H. 32° | L.H. 38° R.H. 32° LEVERAGE | 11/1 | 15/1 | 13/1 | 13/1 | 16.5/1 | 15/1 | 13/1 TURNS OF WHEEL | 2 | 2.300 | 2.225 | 2 1/4 | 3.000 | 2.650 | 2 1/4 H.E.B | ||