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).
Two graphs showing spring poundage against axle weight for 20 HP rear and front springs.
| Identifier | ExFiles\Box 16\7\ Scan092 | |
| Date | 30th August 1928 guessed | |
| 20 HP REAR SPRINGS REAR SPRING POUNDAGE HEAVY LIGHT CAR SPRUNG FOR FOUR PASSENGERS ADD HALF LUGGAGE TO EACH SPRING REAR AXLE WT. CWT CAR EMPTY 20 HP FRONT SPRINGS FRONT SPRING POUNDAGE CONTINENTAL NORMAL CAR SPRUNG FOR FOUR PASSENGERS UNAFFECTED BY LUGGAGE FRONT AXLE WT. CWTS. CAR EMPTY | ||