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. Ltd. requesting tyre radius data for speedometer calibration.
| Identifier | ExFiles\Box 45\2\ Scan293 | |
| Date | 25th August 1930 | |
| 84050. Expl. Dept. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}6/MJ. August 25th.1930. The Dunlop Rubber Co,Ltd., Fort Dunlop, ERDINGTON, BIRMINGHAM. Dear Sirs, 20 HP. & 40/50 TYRES. In 1925 Mr. Healey was good enough to let us have some figures showing the increase in effective radius of our then standard high pressure tyre at speeds up to 80 m.p.h. (Ref: Research Dept. 25th.June 1925). It would be of very great assistance to us if you could arrange to let us have similar figures for our present standard 7" tyre for the 20" rims on 40/50, and 6" tyre for 19" rims on the 20HP; both inflated to 35 lbs/sq.in. These figures would be of considerable assistance to us in calibrating speedometers for high speed work. Yours faithfully, FOR ROLLS-ROYCE LTD. | ||