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 to the Dunlop Rubber Co. discussing observations on wheel wobble with different tyre types.
| Identifier | ExFiles\Box 28\4\ Scan343 | |
| Date | 25th August 1925 | |
| X457 Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}3/LG. Messrs. The Dunlop Rubber Co., Fort Dunlop, Erdington, Birmingham. 25th. Aug. 1925. Dear Sirs, For the attention of Mr. Healey. Development Dept. I thank you for your letter of the 24th. inst. We quite agree that it is possible to have more than one period of wobble on a car. We find that all the periods we get, however, coincide with the wheel revolutions when they start, as you observed, they make it slightly out of step towards the end of the particular period. The point of interest we have found is that we can damp out balloon tyre wobbles fairly easily, whereas we have much more difficulty in damping out the higher frequency oscillations due to high pressure tyres. We are concluding that the greater amplitude of the balloon tyre wobble gives us more movement in which to apply our frictional or hydraulic resistance. We also think it may be of interest to you to know that we calculate from our Chronograph record, estimating the wobble to be S.H.M. that the greatest amplitude we have so far obtained is about 19°. We will let you have any further practical information on this subject which we think will be of interest to you. Yours faithfully, | ||