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).
Table of specifications for various outer and inner springs.
| Identifier | ExFiles\Box 95\3\ scan0018 | |
| Date | 31th August 1934 guessed | |
| X346 TABLE (1). PARTICULARS OF OUTER SPRINGS. Spring Designation. | A.O. | B.O. | C.O. | D.O. Wire Dia. | 0.625" | 0.650" | 0.650" | 0.650" Mean Dia. of Coils. | 4.15" | 4.175" | 4.175" | 4.175" No. of coils (effective) | 7 | 7 | 7 | 7 Normal Load. | 1750 lbs. | 2001 lbs. | 2076 lbs. | 2131 lbs. Deflection to normal position. | 3.825" | 3.815" | 3.950" | 4.065" Free Length. | 10.825" | 10.815" | 10.950" | 11.065" Max. Load. | 2426 lbs. | 2775 lbs. | 2850 lbs. | 2905 lbs. Max. Stress (Uncorrected) | 105,000 lbs/sq.in | 107,500 lbs/in2 | 110,400 lbs/in2 | 112,700 lbs/in2 Min. Deflection. | 5.300" | 5.290" | 5.425" | 5.540" Rate per inch. | 457.5 lbs. | 525 lbs. | 525 lbs. | 525 lbs. Rate per inch at wheel. | 62.6 lbs. | 72 lbs. | 72 lbs. | 72 lbs. Normally part of combination. | 1000 lbs/wheel. | 1100 lbs/wheel. | 1200 lbs/wheel. | 1250 lbs/wheel. PARTICULARS OF INNER SPRINGS. Spring Designation. | A.1. | B.1. | C.1. | D.1. Wire Dia. | 0.464" | 0.462" | 0.487" | 0.495" Mean dia. of coils. | 3.00" | 3.012" | 2.987" | 2.980" | ||