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).
Selection of suspension systems for Wraith II and Bentley models, comparing weights, costs, and development strategies.
| Identifier | ExFiles\Box 87\4\ scan0113 | |
| Date | 27th March 1936 | |
| It was decided that we should use Ph.III suspension for Wraith II at a time when it was found (1) that the 25 HP. chassis manufacturing cost was far too high (11) that Ph.III front suspension cost was far in excess of Ph.II front axle. This decision was found necessary in order to save the time of developing a simpler suspension system. The attached figures showing a comparison of the weights of Wraith II front end and that of the 25 HP. There is an increase of 126 lbs. For Ph.III the increase in weight of the front end is 60 lbs. over that of Ph.II. For Bentley, where the performance is imperative, the increase of 120 lbs. for independent suspension is impractical. It is essential, therefore, that a simpler type of suspension be used for this chassis. We also give estimated weights for a torsion bar type of suspension for Wraith II. This gives a saving of 106 lbs. At the moment everybody may be of the opinion that Bentley will have a torsion bar system, but the majority of people thought that Wraith II would have a simpler suspension system than that of Ph.III. We think it is improbable that Bentley independent suspension system will come through with much greater speed than the Ph.III scheme, development work on which has only just been completed after 18 months on the road. We think that the decision to try a torsion bar system for Bentley is all right, but in view of the fact that there is no torsion bar car made which gives the required degree of comfort, a considerable amount of development will be necessary. Although we know that Olley is trying and is in favour of torsion bar systems, the risk of waiting until America produce a car for us to copy is not small, as the present American wishbone system with exposed springs is light and cheap to produce in large quantities. We suggest that we should buy one of the new 7-seater 15 HP. Citroen cars, price £345 retail, which are now available in France, and which we would be prepared to alter in order to obtain softer suspension and larger wheel movements to give the required degree of comfort. In order to try a torsion bar system on the Bentley we could fit the complete front suspension assembly (less engine) from the | ||