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).
Specification sheet detailing the particulars of four different inner spring designs.
| Identifier | ExFiles\Box 95\3\ scan0019 | |
| Date | 31th August 1934 guessed | |
| SHEET (2) PARTICULARS OF INNER SPRINGS (2). Spring Designation. | A.1. | B.1. | C.1. | D.1. No.of coils (effective) | 9 | 9 | 9 | 9 Normal Load. | 950 lbs. | 971 lbs. | 1163 lbs. | 1243 lbs. Deflection to normal position. | 3.325" | 3.485" | 3.310" | 3.295" Free Length. | 10.000" | 10.160" | 9.985" | 9.970" Max. Load. | 1372 lbs. | 1381 lbs. | 1682 lbs. | 1800 lbs. Max. Stress (uncorrected). | 105,000 lbs/in2 | 107,500 lbs/in2 | 110,400 lbs/in2 | 112,700 lbs/in2 Max. Deflection. | 4.800" | 4.96" | 4.785" | 4.77". Rate per inch. | 286 lbs. | 278 lbs. | 352 lbs. | 378 lbs. Rate per inch at wheel. | 39.2 lbs. | 38.2 lbs. | 48.3 lbs. | 52 lbs. Normally part of combination. | 1000 lbs/wheel. | 1100 lbs/wheel. | 1200 lbs/wheel. | 1250 lbs/wheel. | ||