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).
And a diagram showing track variations on a Bentley 4 1/4 Litre front axle when jacked up.
| Identifier | ExFiles\Box 84\3\ scan0230 | |
| Date | 28th July 1934 | |
| Title BENTLEY FRONT AXLE x201 4 1/4 Litre Latest Type Pointer Front Wings Track ROAD SPRING B A C Variation in track when axle is packed up. | | O.S. | N.S. | Difference | |---|---|---|---| | Normal. | .075+ | .100+ | | | Centre Jack. A | .250- | .200- | -.625" | | 2 Jacks. B+C. | .125- | .115- | -.415 | | ||