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).
Comparative test report on suspension performance for the Phantom and 20 HP models.
| Identifier | WestWitteringFiles\O\2April1926-June1926\ Scan016 | |
| Date | 7th 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.Robotham. | ||