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).
Recommendations to improve the high-speed performance of the 40/50 suspension system.
| Identifier | ExFiles\Box 16\7\ Scan067 | |
| Date | 19th May 1928 | |
| To Hm{Capt. W. Hallam - Head Repairs}, from Hs{Lord Ernest Hives - Chair}/Rn.{Mr Robinson} XJL40 Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}2/LG19.5.28. 40/50 SUSPENSION. (For Depot sheet) XJL40 Complaints come to our notice that the 40/50 suspension is not satisfactory at high speeds. The most recent example is that of 9-TC Prince Ibrahim. The normal 40/50 HP. suspension is not arranged for the best results at maximum speed. However, by suitable adjustment of the road spring rating and damping, the high speed road holding characteristics of the car can be vastly improved. This also improves the steering which invariably gives the driver a feeling of insecurity above 60 m.p.h. if there is insufficient damping in the suspension. These points were emphasised in The Technical File Part 16. pages 8 and 9. Therefore, in cases such as that of Prince Ibrahim we make the following recommendations : The rear road spring rating should be increased 25%. Normally this would result in the car being raised 2" at the rear. However a number of standard springs are available at the Works termed 25% stiffer springs. These have 1.4" initial camber instead of the normal 3.2" and are suitable for light open touring cars. When they are fitted the rear of the car is lowered .75" instead of being raised 2.0" as would happen if the ordinary spring with 25% increased rating were used. If the body designe give sufficient clearance, .5" should be cut off the rear buffers to increase immunity from bumping. contd :- | ||