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 a Bentley owner to The India Tyre & Rubber Co. Ltd. regarding correct tyre pressures after driving.
| Identifier | ExFiles\Box 29\4\ Scan198 | |
| Date | 22th June 1934 | |
| COPY. THURLASTON, Nr. RUGBY. 22nd June, 1934. The India Tyre & Rubber Co. Ltd., Inchinnan, Scotland. Dear Sirs, I am using a set of your India Speed Special Tyres on my 3½ litre Bentley. According to the recommendations of the Bentley Company these tyres are inflated to 35 lbs. per sq. inch in the front and 30 lbs. per sq. inch on the rear, with the tyres cold. After running the car at 60 m.p.h. for ½ hour the pressure of the rear tyres was found to have risen to 37 lbs. caused by the heat of the tyre expanding the air. As the car is normally driven at or round 60 m.p.h. it is obvious that instead of the air pressure in the tyre being 30 lbs. it is usually in the neighbourhood of 37 lbs., which makes the riding correspondingly harder. I should be interested to know what you have to say about this matter, and to have your recommendations as to what air pressure should be used in the front and rear tyres on this car when measured at atmospheric temperatures. Yours faithfully, (Sgd.) Bernard Hopps. | ||