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).
High-speed steering wobbles, tyre pressures, and the potential of hydraulic dampers.
| Identifier | ExFiles\Box 29\1\ Scan186 | |
| Date | 17th February 1926 guessed | |
| contd :- -2- We have a Hispano car and on this we can produce high speed wobbles. We have recently tried a new Cadallic car which developed the high speed steering wobble during the trial run. We know that certain makers are fitted[ing] low pressure tyres to their cars. In most case they still use the same tyre pressures as we use for normal tyres. As long as high pressures are used, we do not expect these tyres to affect wobbles to any marked degree, but no advantage would be gained in comfort by the larger tyres unless considerably lower pressures are used. We fully realise the danger and seriousness of high speed steering wobbles and it is for this reason that we do not recommend fitting tyres which would encourage customers to run on low pressures. At the same time we shall not be satisfied until cars are made so that low pressures can be used with safety. We anticipate shortly fitting to our cars hydraulic dampers on the front which we have proved will greatly reduce the tendency for wobbles to build up and yet not spoil the car in other directions. As regards your present car. From our experience we should expect it to be free from high speed steering wobbles as long as the front wheels are balanced, the tyre pressures kept at 45 to 50 lbs., and the front shock absorbers set at 35 to 40 lbs. The fact that you state, going over a rough road gives you the impression that wobbles are contd :- | ||