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).
Letter from the Rapson Tyre Company regarding tyre balance issues causing steering wobble on new car models with four-wheel brakes.
| Identifier | ExFiles\Box 28\4\ Scan221 | |
| Date | 18th December 1924 | |
| -3- 18th. December, 1924. As I understand the Rolls-Royce cars to which our Oversize tyres were fitted and tried in France were of the new four wheel brake type, it certainly seems that in that instance neither the tyres nor the front wheel brakes gave trouble. If you have one of these cars fitted with four wheel brakes still over in France and you would permit me to use this on the new Monthlery track just outside Paris, I would prefer to cross over and conduct my experiments there rather than come to Derby, where it must be difficult to find a suitable space where maximum speed can be maintained for any length of time. I trust that you will retain the tyres which you tried and which proved to be out of balance, so that I may get down to the actual cause of the trouble on these. There is one significant point which strikes me in connection with the steering wobble which has been caused on His Royal Highness' car due to the tyres being out of balance and it is one which I think should receive your serious consideration. - I refer to those tyre replacements fitted by your customers after the standard tyres which were fitted at your Works have failed or worn out. Nothing is more certain than that in the hands of private users, the question of balance will be completely ignored. If a tyre fails, the user will stop at the nearest garage and purchase a replacement of any make he chooses. Even though he should use his spare wheel to effect the preliminary change, it is certain that the tyre he has purchased will eventually be brought into use and it is quite possible that this will not only be out of balance, but be run opposite a worn tread, which again affects the steering, because the circumference of the periphery of the worn tread is considerably less than that of the new tyre. I have personally weighed and balanced various sizes of tyres we have at these Works and have found the difference only amount to ounces in weight, which is exceptionally good in view of the fact that it is not possible to run rubber with anything like the same accuracy as metals. The difference in balance occurs in all makes and whilst from your large stock of the tyres you standardise you may be able to select in the first instance tyres of identical weight and balance for use on your front wheels, I maintain that eventually it is inevitable that the user will not go to the same trouble and if your steering is going to be affected, as it apparently is, on your new model by this question of balance, it certainly needs looking into. Trusting that in reading foregoing you will not think I am making excuses, but endeavouring to convey to you my feelings and my natural desire to tackle and overcome the difficulty that has arisen. I beg to remain, Yours faithfully, (Sgd) F.{Mr Friese} Lionel Rapson, Governing Director, RAPSON TYRE AND JACK COMPANY, LIMITED. | ||