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).
Internal memorandum discussing steering wobble issues and recommended tyre pressures for different car types.
| Identifier | ExFiles\Box 71\4\ scan0311 | |
| Date | 20th August 1925 | |
| To CJ. from BJ. c. to BY.{R.W. Bailey - Chief Engineer} Hs.{Lord Ernest Hives - Chair} BJ17/H20.8.25. STEERING. In the memorandum dictated at 10-30 a.m. and read to you on the telephone this morning, I mentioned that P.N. had experienced no wobbles during the last 500 miles on our demonstration car, with the tyres at 55 lbs. pressure and balanced wheels. I have just received a telephone message from BY.{R.W. Bailey - Chief Engineer} and Hs.{Lord Ernest Hives - Chair} that they agree that no wobbles have been experienced with any car fitted with balanced wheels and tyre pressures over 50 lbs. This includes all the tests made in France. The cars tested in France had front tyre pressures of 50 lbs. or more, as they were to run at high speeds. It seems a pity that cars should be tested for 10,000 miles under non-standard conditions (which differ from our advice to customers in our Instruction Book, which is - lbs. (see below) Should we not advise them in future to make their tests in exact accordance with instructions we give customers, including tyre pressures, lubrication, etc?) I telegraphed you today,- therefore, as follows :- "Hives and Bailey agree perfectly safe issue cars provided "customers are advised to keep front tyres at over fifty "pounds pressure and wheels balanced. No trouble in all "tests made in France and elsewhere with tyres over fifty "pounds pressure. Northey considers fifty to fifty-five "pounds reasonably comfortable Possibly fifty-five pounds "is safest pressure to quote customers Have stopped deliv- "eries pending your decision". B.J. Front tyres (closed cars) 55 lbs. per sq.in. Front tyres (open cars) 45 lbs. per sq.in. Rear tyres (closed cars) 65 lbs. per sq.in. Rear tyres (open cars) 55 lbs. per sq.in. | ||