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).
Tyre noise tests for the Phantom III, comparing Dunlop and Goodyear tyres and the effects of rubber insulating bushes.
| Identifier | ExFiles\Box 157\2\ scan0042 | |
| Date | 30th September 1936 | |
| X1332 To E.{Mr Elliott - Chief Engineer} c. to Sg.{Arthur F. Sidgreaves - MD} c. to Wor.{Arthur Wormald - General Works Manager} c. to By.{R.W. Bailey - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} c. to Mx.{John H Maddocks - Chief Proving Officer} Hs{Lord Ernest Hives - Chair}/Wym.{G. Harold Whyman - Experimental Manager}33/KW.30.9.36. Phantom III Tyre Noise. We have just concluded a series of tyre tests in London on 33-EX car, with the latest type of Dunlop tyre with the outside edges filled in, and a set of Goodyear tyres, both sets of tyres being in a partly worn condition which we know is the worst period for groans. The car was first driven around London streets as a standard car; i.e., rubber body mounting and rubber pads between the rear axle and spring seat. The Dunlop tyre proved to be the better of the two makes for groan, the only noticeable periods being at 20 M.P.H. and 11 M.P.H., but very much lighter than any other Dunlop tyres we have tried. The Goodyear tyres had a more pronounced groan around the 20 M.P.H. period and spread over a larger range. At the lower speeds they were quite good. We then fitted rubber insulating bushes to the front end shackles of the rear springs and repeated the tests. The 20 M.P.H. period on the Dunlop tyres was completely "ironed" out, and the 11 M.P.H. period slightly improved; in fact the car was very good for tyre groan generally. The rubber shackles did not have quite the same effect on the Goodyear tyres, as the groans, although improved, were still objectionable and the period of still longer duration i.e., 22 M.P.H. to 15 M.P.H. The fitting of rubber shackles does however definitely interfere with the stability of the car, and also causes the footbrake pedal to "pump" when braking hard at high speeds. Hs{Lord Ernest Hives - Chair}/G.H.Whyman. | ||