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).
Bumper test report for a front spring, detailing Brinell hardness results and failure analysis for each leaf.
| Identifier | ExFiles\Box 80\2\ scan0216 | |
| Date | 21th September 1920 | |
| HS{Lord Ernest Hives - Chair} X2628 BUMPER TEST - FRONT SPRING F.4625 - 950 lbs. 11 leaves, with tie clips 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. | ||