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).
Test report on the springing and shock absorber performance of Mr. Sidgreaves' car 43-KR, before and after alterations.
| Identifier | ExFiles\Box 65\4\ scan0142 | |
| Date | 18th October 1929 | |
| S.G. copy to C. " " H.{Arthur M. Hanbury - Head Complaints} RE: MR. SIDGREAVES' CAR 43-KR. As arranged, I tried the above car on the 4th inst. with a view to obtaining the characteristics of the springing, before W. made various experiments on the shock absorbers. Tests were carried out with the driver and one passenger one spare wheel at the rear and one on the nearside; tire pressures were at 38 on the front and 35 on the rear. I thought the springing poor at speeds below 10 m.p.h. and 'dithering' and jolting were conspicuous on anything but a good road. At speeds around 15 m.p.h. the action of the shock dampers was pronounced, it being extremely difficult to read a paper. At 20, the dithering and jolting I thought was at its worst. At 25-30 m.p.h. the riding was slightly better, but when travelling over rough roads, 'dithering' would frequently shake the whole car and the passengers. At 35 m.p.h. it greatly improved, but the shock absorbers were still too effective. At 40 and over, the springing was really good. There was no trace of harshness and the car was extraordinarily steady, the road holding qualities being extremely good. The springs gave me the impression of being far too strong all round for anything but Continental use. I can only imagine that the interleaf friction had greatly increased on account of digging-in and by roughness of the spring leaves. The shock dampers appeared too effective at low speeds, resulting in an abrupt termination of the rebound action action of the springs. After W. had completed their alterations, I again tried the car on the 17th Inst. travelling from Bletchley over the same roads as previously. The tire pressures were as before. One spare wheel was on the offside instead of the n/s, as W. considered that in this position, the car was better balanced. I immediately noticed a most decided improvement, the car riding over pot-holey and rough roads with a great decrease in the dithering and the rear shock absorbers did not appear to control the action of the springs at the lower speeds, as had been the case hitherto, - more especially as regards rebounds. The improvement was most marked up to speeds of 35 m.p.h. and gave me the impression that the car had been sprung with very much more flexible springs. At 35-45 m.p.h. the car rode very comfortably, being reasonably steady on the | ||