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).
Specifications for a front spring, detailing the number of plates, their thickness, and clip centre measurements.
| Identifier | ExFiles\Box 52\2\ Scan206 | |
| Date | 21th January 1930 guessed | |
| FRONT SPRING 5 Plates .36 Main Plate .35- Other four plates Total thickness 1.76" Clip Centres 35" & 15 3/4" | ||