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).
Comparison of Dubonnet and wishbone suspension systems, detailing their respective features and drawbacks.
| Identifier | ExFiles\Box 170\2\ img187 | |
| Date | 3rd May 1934 guessed | |
| -2- (5) For bump and rebound stops - in the wishbone system there is a ratio for the coil spring and a much higher ratio for the shock absorber whereas in the present Dubonnet system the ratio of the coil spring and the ratio of shock absorber are exactly the same and form one ensemble, as this ensemble is housed in one box, the shock absorber being inside the spring, the entire box serves as an oil reservoir permitting a constant renewal of fresh oil for the shock absorber, thereby avoiding any variation in the working power of the shock absorber. (6) For jacking up the wheel the same difficulties are encountered in all systems of independent wheels. (7) There is no doubt there is a definite economy in wear on tires in the Dubonnet system as it is the only system existing which never changes track or camber. (8) The ensemble of the Dubonnet system is not heavier than the wishbone system for the same weight of material. It is certain that with a perfect but difficult assemblave and if there were no play in any of the very numerous joints, one could obtain for a certain time in the wishbone system a satisfactory steering, but as soon as these joints are a bit worn there are violent kicks in the steering wheel. As these many joints are constantly exposed to dust and mud it is easy to understand that the wear is rapidly noticed. The unquestionable advantages of the Dubonnet system over all other systems of Independent Suspension:- (1) The steering being sprung weight all reaction and shimmy are eliminated regardless of wheel action. (2) The wheel always stays in its trajectory without change of track or camber. (3) Complete absence of joints as all articulations are enclosed in a box and are properly oiled at all times. | ||