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).
On car performance, detailing the effect of out of truth and out of balance tyres on steering.
| Identifier | ExFiles\Box 158\1\ scan0009 | |
| Date | 14th January 1927 guessed | |
| FUNDAMENTALS OF CAR PERFORMANCE - TYRES. I: THE EFFECT OF TYRES ON STEERING. (a) Out of truth and out of balance tyres. With the advent of low pressure tyres, steering susceptibility to small defects in these items has become more and more pronounced. It is not too much to say that in the case of a complaint of unsatisfactory steering at high speeds, the first point to be investigated should be the tyres. Covers that have been used on the rear, especially if subjected to violent braking, should not be used on the front. The reason for this is that if a tyre has a flat on it due to the wheel being locked at some time, it is useless to fit it on the front axle and expect it to function satisfactorily, even if correctly balanced. The tread irregularity will transmit a periodic force to the axle and tend to promote a wobble. Sometimes tyres, when they leave the Factory, have treads of varying section, some portions having greater resilence than others. This is more or less inevitable owing to the nature of the rubber and the impossibility of working to fine limits in moulds. When this occurs, and it is not by any means unusual, the tyre has inherent wobble promoting tendencies even when it is new. We have established the fact that a pair of new tyres can spoil the steering of a car if they happen to suffer from this defect in manufacture. It is therefore always worth while trying several different pairs of tyres on the front of a car in the case of a high speed steering complaint. contd :- | ||