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 caused by using low-pressure tyres on 40/50 HP cars fitted with front-wheel brakes.
| Identifier | Morton\M3.5\ img034 | |
| Date | 20th April 1925 | |
| R.R. 493A (50H) (D.B. 175 25-9-24) J.H.D. EXPERIMENTAL REPORT. REF: Hs{Lord Ernest Hives - Chair}1/LG20.4.25. Expl. No. To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to CJ. SJ. c. to RG.{Mr Rowledge} E.{Mr Elliott - Chief Engineer} c. to DA.{Bernard Day - Chassis Design} EY. c. to Wor.{Arthur Wormald - General Works Manager} LOW PRESSURE TYRES. X.457 49830 STEERING WOBBLES. If we use low pressure tyres on 40/50 HP. cars fitted with front wheel brakes, we get high speed steering wobbles. A set of wheels and tyres were sent to France to run on one of the standard 40/50 HP. cars fitted with front wheel brakes. It was impossible to run with these tyres fitted. High speed steering wobbles are very terrifying. The effect, if anything, is more violent than the low speed wobbles and the fact that it occurs at high speeds (60 m.p.h. and over) makes it very much more dangerous. We believe if once a customer experienced high speed steering wobbles, he would lose confidence in his car. For that reason we are not recommending low pressure tyres on front wheels. We are very near the point of high speed steering wobbles with the standard tyres. With the medium low pressure tyres (6.75" dia.) we get high speed steering wobbles. The problem of high speed steering wobbles is not confined to R-R cars, it is a general complaint of all cars to which low pressure tyres are fitted and this is one of the chief reasons that low pressure tyres have had a set back. We have actually made experimentally a spring damped pendulum lever to the patented suggestion made by you contd :- | ||