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).
Wheel and tyre noise testing on a Phantom III, comparing different setups with a Cadillac.
| Identifier | ExFiles\Box 157\1\ scan0223 | |
| Date | 16th October 1935 guessed | |
| Cadillac wheels so that they could be fitted to Phantom 3. The tyres on these wheels were Dunlop worn buttress type on the front, and Dunlop silent tread unworn on the rear. They were exactly as tried on the Cadillac, and on Phantom 3 they produced by general consent the least noise of anything tried, but still not as good as when on the Cadillac car. As a check on this experiment the Phantom 3 was then fitted with its original wheels and tyres but did not then show up as badly as when originally tested, no doubt due to some cause such as the wheels getting changed round. The typical periods and groans however were still present although in more subdued form. Summarising the results, these can be given as follows in comparison with the Cadillac:- Cadillac - 100. P.3. with Dunlop wheels and Dunlop 90 tread tyres - 40. P.3. with Dunlop wheels and Goodrich tyres - 60. P.3. with Dunlop wheels and Dunlop 90 tread tyres, wheels damped - 50 to 60. P.3. fitted with Cadillac wheels and tyres as run on Cadillac - 80. Taking the results from the above table it could be argued that the Cadillac wheels fitted with Goodrich tyres might give a result as good as the Cadillac. It should be remembered that 35-EX has a brand new body which has not done more than six hundred or seven hundred miles in short runs on the road, whereas the Cadillac car has now put up a considerable mileage and has been stripped down and reassembled. We believe this is a definite factor of coachwork resonance. We have had the Dunlop man here today, with a view to obtaining a wheel similar to the Cadillac, together with other types of wheels for experimental test. We expect to have some of the former available very shortly. Now that this tyre noise has arisen so definitely on Phantom 3 as a complaint we intend to follow it up and achieve a standard beyond that which is accepted on our existing products. | ||