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 12 different engine mounting configurations and their resulting effect on road vibrations.
| Identifier | WestWitteringFiles\K\October1923\ Scan3 | |
| Date | 12th July 1923 guessed | |
| 2-SO/MARK-11. No. | Particulars of Mounting. | Effect on the road. ---|---|--- 1 | Standard G.11. engine mounting. | Bad vibrations at 15 m.p.h. Slight " " 12 m.p.h. 2 | Standard mounting with friction added. | Great improvement all round - slight period felt at 12 m.p.h. 3 | Standard mounting with weight added to balance engine about centre of gyration. | Bad period at 11 m.p.h. - smooth above 12 m.p.h. 4 | As No.3 with friction added. | Considerable improvement at slow speeds but slight period at 12 m.p.h. 5 | Engine mounted on centre of crankshaft - torque taken on spring controlled arm at the front end. | Bad - generally rough periods at 12 and 17 m.p.h. 6 | As No.5 with friction added. | Great improvement over No.4. but slight period at 17 m.p.h. 7 | Engine mounted on centre of crankshaft - solid torque arm at the front with friction. | Very good all round - slightest period at 17 m.p.h. 8 | As No.7 with friction removed. | Slight period at 17 m.p.h. - small period at 11 m.p.h. 9 | Engine mounted on centre of crankshaft - weight added to balance about centre - solid torque arm at front. | Very good - no noticeable periods - slight sense of roughness. 10 | As No.9 with friction added. | Very little different to No.9. A general feeling of smoothness. 11 | As No.10 with spring controlled torque arm. | Very good - slight period at 16 m.p.h. 12 | As No.11, with friction removed. | Better than with friction on for very slight period at 16 m.p.h. but slight slow speed period at 8 m.p.h. which the friction removed. | ||