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).
Implications of fitting an overdrive gearbox to Wraith and Bentley models, including changes to size, weight, cost and performance.
| Identifier | ExFiles\Box 86\4\ scan0168 | |
| Date | 17th April 1937 guessed | |
| (sheet 2) There is an increase of size, weight and cost with the overdrive box. We know that the shaft centres must be increased from 3.2" to 3.5", but we do not yet know whether anything more must be done to improve the capacity of the gears and bearings to take the full power more or less continuously. If we have to have the same gearbox casing for all models of Wraith and Bentley we shall have an increase of weight and cost on all cars regardless of how many have the overdrive ratios. In view of the fact that the weight of the Bentley is increasing and is likely to go on increasing, it seems to us that we should avoid further reduction of performance by the use of a three speed box unless we can restrict the overdrive box to use almost entirely on the Continent. We believe that with the new engine mounting, which should come into use with Bentley III, there will be very little need to reduce the engine speed for the sake of avoiding unpleasantness from the engine, at all events in this Country. E/HDY.{William Hardy} | ||