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).
The effects of balloon tyres on high-speed steering wobbles and road shocks, with reference to the Silver Ghost.
| Identifier | ExFiles\Box 178\1\ img128 | |
| Date | 13th July 1926 guessed | |
| - 29 - bound point in the tyre tread exerts a pull of 160 lbs. at 60 m.p.h. so that there is an alternating couple of more than 300 ins. lbs. trying to turn the wheel in and out. (b) Balloon tyres. Another point that we have established is that the tendency of a car to suffer from high speed steering wobbles has a direct bearing on the road shocks likely to be felt by the driver. Thus, balloon tyres, though they improve the riding qualities of the car enormously, frequently affect the steering adversely, even though high speed wobbles are not actually experienced. The road wheels appear to be in a state of unstable equilibrium and 'Echo' road shocks they receive. Another example of the same thing came up when front wheel brakes were fitted to the Silver Ghost. The steering was in no way altered and the increase in dead weight on the front wheels was very little. The road shocks felt by the driver, however, were very definitely much worse for the change. The only item that was really badly affected by the alteration was the criss cross or wobbling period of the front axle, which was lowered considerably as most of the added mass was at the extremities of the front axle. We are therefore of the opinion that high speed wobbles and road shocks have a great deal in common. We find that centre-point steering seems to augment road shocks. Also that weak side steering tube springs can effect a large improvement. The alteration that can be effected in these contd. | ||