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).
List of springs fitted to experimental cars with corresponding complete car weights.
| Identifier | ExFiles\Box 16\7\ Scan183 | |
| Date | 1st June 1929 | |
| To BY/SS.{S. Smith} from Hs{Lord Ernest Hives - Chair}/Rn.{Mr Robinson} X7410 Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}1/LG3. 6. 29. 47840 The following are springs which we have fitted successfully to experimental cars :- Complete Springs car wt. fitted. 18-EX 44 cwts. 2 qrs. Front 1000 Rear 1100 19-EX Front 1100 Rear 1350 20-EX 47 cwts. 3 qrs. Front 1100 Rear 1300 21-EX 48 cwts. 2 qrs. Front 1100 Rear 1350 22-EX 48 cwts. 2 qrs. Front 1100 Rear 1350 23-EX No body. Hs{Lord Ernest Hives - Chair}/Rn.{Mr Robinson} | ||