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).
Summary of conclusions regarding vehicle noise issues, specifically tyre noise and transmission chunking, with comparisons to American cars.
| Identifier | ExFiles\Box 173\4\ img212 | |
| Date | 5th November 1935 | |
| (sheet 2) Following is a resumé of the conclusion we came to on most of the problems discussed, following the order of Mr Elliott's E.3/MP.5.11.35. (1) Tyre Noise. The Tyre Co's consider that as far as the American market is concerned they have overcome tyre noise to the extent that they are now seldom bothered by the Motor Co's. They admit that no tyre with adequate non-skid and traction properties is free from noise, but by variation in the pitch of the studs, and introduction of plain ribs where possible they have so far reduced noise that it is no longer an outstanding trouble. The difference between our car and the American cars, so far as we could see, lies in the use of rubber between the wheel or axle, and the frame, and possibly between the frame and the body. Most people have rubber between the rear axle and the springs, and many between the front wheels and the springs. In the case of some front assemblies, where there is no rubber, front tyre noise is the major trouble. Rubber fabric shims between the frame and the body were nearly universal, their function being primarily to reduce noise inside the body. If we can overcome the steering and control troubles which may arise from it (and it seems likely we can) it is probable that we shall, by the use of rubber, be able to make our cars as noise free as the Americans, and do the rest by the tyres. We have brought home samples of the rubber between the rear axle and the spring, and also between the frame and the body. The body, dash, floor etc. in American cars are more heavily noise insulated than anything we have so far done. We have brought home some specimens of the noise insulation used by Briggs. When one considers the amount of noise insulation used, it seems probable that American transmissions etc. are more noisy even than they appeared to be. (2) Chunking in the Transmission. There were a variety of explanations and cures of this trouble, but the only car which seemed to have really cured it under all the conditions which we saw was Buick. Their method is to tighten up the total clearance in the whole transmission, but to pay especial attention to the clutch hub | ||