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).
Technical note on the Wraith's ride quality and standard damper settings.
| Identifier | ExFiles\Box 9\5\ 05-page243 | |
| Date | 10th April 1939 | |
| Handwritten notes: APM See me, Rm.{William Robotham - Chief Engineer}, File To: H.{Arthur M. Hanbury - Head Complaints} Levallois Bd.{Mr Berend} Mr. Hives c. S/C - C c. RM{William Robotham - Chief Engineer} c. LA{L. A. Archer} c. RH{R. Hollingworth}/GWH{George W. Hancock - Head Chateauroux} (H) c. RM{William Robotham - Chief Engineer}/HV c. MS. at/D.2/10.4.39 WRAITH RIDE Although the general opinion is that the Wraith suspension is very good and gives an excellent ride, certain criticisms have been made that it is too soft or flexible, producing in some cases a feeling of sickness. This so-called softness is really a slow-period pitching motion, and it is aggravated if the design of the body is such that there is a lot of overhang at the back. The pitching motion is most exaggerated over certain types of undulating road surfaces. Although in one particular case we have had to make a pair of higher rating rear springs to deal with a bad complaint of pitching, this normally should not be necessary, as we find that a vast difference can be made by suitable alterations to our damping. The standard setting of the Wraith dampers is as follows:- Front Initial load. 40 lbs. Leak ......... 5 secs. Produced by one .031" dia hole in each valve. Rear Initial load. 40 lbs. Leak ........ 2 secs. Produced by one .040" dia. hole in each valve. The drilling of the valves consists of one .062" dia. hole through the neck, and the actual leak hole referred to above is drilled through the centre of the head of the valve | ||