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 India Tyre & Rubber Co. Ltd. providing feedback on tyre testing, including cornering, silence, and oversteer performance.
| Identifier | ExFiles\Box 157\6\ scan0167 | |
| Date | 23th September 1937 | |
| Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls}1/AP. Sept.23rd.1937 The India Tyre & Rubber Co.Ltd., Inchinnan, SCOTLAND For the attention of Mr.P.Worth Dear Sirs, We have now had an opportunity of trying the four more silent variety of 6½ X 17 tyres which you sent us for test. As regards silence, we would consider these tyres satisfactory. Before we carried out any tests on the Skid Pan as to their cornering ability, one of our drivers had already complained of their behaviour on the road when taking a fast corner. We therefore carried out tests on the Skid Pan by fitting the noisy type of tyre on the front and measuring the relative amount of oversteer with the noisy and silent on the rear. The increase in oversteer with the new silent tyre was in the ratio of 28-18, and the maximum obtainable sideways acceleration about 10% less. These tyres, therefore, cannot be considered satisfactory from this point of view, as we loose almost all the benefit of changing from the 5½ to 6½ tyre. We note from your letter that you are sending us a second set to test, but are wondering whether it would help you if we returned the first set for any modifications which you could make. With regard to some other experiments we have been carrying out, we wondered whether you have any figures for the effective running radius at 90 miles an hour of a 5½ X 18 tyre and the 6½ X 16, both at 30 lbs. pressure and axle weight of 20 cwts. Yours faithfully, FOR ROLLS-ROYCE LTD. | ||