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 ground clearances for the 28-EX model when both axles are clamped to the buffers.
| Identifier | ExFiles\Box 11\5\ 05-page208 | |
| Date | 23th November 1934 guessed | |
| V7941 28-EX Ground Clearances when both Axles are clamped on to the Buffers. Under Front Axle 8" " Jackall Jacks 4½" " D.W.S. Jacks 7" " Crankcase 6½" " Front Stg. Arm s.s. tube 7½" " Battery Box 3½" " Rear Silencer 4½" " Front Silencer 5½" " Rear Bango Cross Member 3½" " Fish Tail 6" | ||