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 detailing the weight of a 4.EX car with and without passengers.
| Identifier | ExFiles\Box 3\2\ 02-page081 | |
| Date | 7th September 1920 guessed | |
| S.Fee.. X.200 (Filed 96 625C) File X.200 WEIGHT OF 4.EX CAR. X.3764. Without passengers. Front 1 ton. 0 cwt. 0 qrs. Rear 1 " 3 " 2 " Total 2 " 3 " 2 " With passengers. 1 ton 1 cwt. 1 qrs. 1 " 7 " 2 " 2 " 8 " 3 " [STAMP] EFC JUN 15 RECEIVED | ||