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 discussing the choice of tyre sizes, gear ratios, and ride experience with different tyres.
Identifier | ExFiles\Box 30\5\ Scan130 | |
Date | 26th September 1935 | |
X1336 Exptl. Dept. HS{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}S/KW. 26th September,1935. P. Worth, Esq., The India Tyre & Rubber Co.Ltd., Inchinnan, SCOTLAND. Dear Mr. Worth, Thank you for your letter of the 20th September. With reference to my remark that we could have used smaller tyres, the reason for this was that the ideal rear tyre for gear ratio was 6 x 19, and the 6 1/2 x 19 definitely gave too high a gear ratio The reason we did not fit the smaller tyres was that we had had so little experience with the wear of the India tyres and we wanted to be sure of getting half way through the race. With regard to the 7 x 18" tyres, we have run a set of these, and they are certainly quieter than the Dunlops at low speeds. On the initial runs, however, they seemed to give a harder ride. We are trying them at lower tyre pressures and also we understand that they may get more flexible with use. We will let you know, however, when we have had some more running on them. Yours faithfully, FOR ROLLS-ROYCE LIMITED. | ||