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).
Data table comparing specifications for rear road springs across various car models.
| Identifier | ExFiles\Box 112\1\ scan0071 | |
| Date | 7th January 1938 guessed | |
| REAR ROAD SPRING DATA. Car. Drg No. Length in inches. Width in inches. Top Plate thick-ness in inches. Load in lbs. Initial deflex: in inches. Total deflex. in inches. Remarks P.III. F.89566 66.000 2.500 .340 1500 7.000 11.625 Thick plate spring F.89060 66.000 2.500 .300 1400 7.000 11.600 Wraith III. FW.1477 56.000 2.250 .270 1100 6.400 11.650 B.III. FB.3317 50.000 2.000 .330 1000 4.000 7.000 B.II stand ard. FB.2881 50.000 2.000 .290 1050 4.000 7.125 25/30. HP F.58608 56.000 2.250 .270 1200 6.400 11.150 B.II low rating. 50.000 2.000 .260 900 5.500 9.500 Special low rat-ing expl springs B.50 50.000 2.000 ? 1050 6.000 9.500 Proposal Ev.{Ivan Evernden - coachwork} | ||