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 of suspension performance for the Phantom and 20 HP models under specific road test conditions.
| Identifier | ExFiles\Box 67a\1\ scan0137 | |
| Date | 16th April 1926 guessed | |
| PHANTOM. 20 TO 30 M.P.H. ON A SLIGHTLY WAVY MAIN ROAD. Front shock dampers tightened from 25 to 100 lbs. Definitely worse riding in the back of the car. Rear shock dampers - ditto. Much the same result - effect slightly worse if anything. No shock dampers. Best condition for the particular fault complained of. Weaker front springs. Improvement - relative value not yet decided. Increasing mass over front axle 20%. No measureable improvement. Hydraulic shock dampers 25 and 75 lbs. Better riding than equivalent friction dampers. 20 HP. Front shock absorbers tightened from 25 to 100 lbs. Worse riding in the back of the car. Rear shock dampers - ditto. Ditto. No shock dampers. Best condition for fault complained of - better than Phantom. Hydraulic shock dampers - 25 and 75 lbs. Better riding than equivalent friction shock dampers. Hs{Lord Ernest Hives - Chair}/W. A.{Mr Adams} Robotham. | ||