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).
Front bumper spring test report detailing specifications and results after a durability test.
| Identifier | ExFiles\Box 119\2\ scan0129 | |
| Date | 21th September 1920 | |
| X/1331 BUMPER TEST - FRONT. X.2628. SPRING F.4625 - 950 lbs. 11 leaves, with tie clips X.1331 also nibs and slots, tapered ends. Fitted on O.S. Bump chassis 30.8.20, (standard spring). No. of leaves. | Brinell. | Remarks. | Time run. 1 | 415 | Broken 6" from rear. | 2 | 444 | O.K. | 3 | 444 | O.K. | 4 | 415 | O.K. | 5 | 415 | O.K. | 10 hrs. 40 mins. 6 | 444 | O.K. | 7 | 444 | O.K. | 8 | 444 | O.K. | 9 | 444 | O.K. | 10 | 415 | O.K. | 11 | 415 | O.K. | Spring taken off 21.9.20. | ||