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).
Causes and proposed solutions for high-speed steering wobble, believed to be an epidemic caused by lower pressure tyres.
| Identifier | ExFiles\Box 28\4\ Scan267 | |
| Date | 13th August 1925 | |
| +457 To CJ. from R.{Sir Henry Royce} c. to BJ. Wor.{Arthur Wormald - General Works Manager} c. to Hs.{Lord Ernest Hives - Chair} PN.{Mr Northey} BY.{R.W. Bailey - Chief Engineer} RE. STEERING. R2/M13. 8. 25. X. 8430 X. 457 With reference to the visit of PN.{Mr Northey} and Hs.{Lord Ernest Hives - Chair} today, we have come to the conclusion that this phenomenon of high speed steering wobbles is a recent epidemic probably caused by lower pressure tyres etc. Everybody is troubled with it more or less, including motor-cycles. We have nothing abnormal to cause it, but we are meeting the situation by increasing the friction damping both by a damped spring friction lever and by an additional hydraulic damper we propose to carry on the front axle, both being applicable to New PhantomCodename for PHANTOM I cars and the latter to Silver Ghost cars. These will probably be adopted together with a slower and more irreversible steering, which enables us to adopt more damping friction. I consider that the hydraulic damper carried on the axle is particularly effective for this purpose, as the viscosity of the liquid will cause considerable resistance to high speed vibrations, but should make no difference to slow speed motion of steering - (though these additional fittings are extremely undesirable.) I believe they are now pushing on with all other experiments already instructed at the Works. We are adopting this course so as to permit of the wheels being more out of balance. In the meantime we are getting the tyre makers to revert to their system of supplying only well balanced wheels, inner tubes, and covers. There is no doubt that some of Dunlops inner tubes are bad for balance, and should be abandoned. I have just one idea that may shew some light on the subject, which should be tested without delay. It suggests that we may have hit some unfortunate flexibility. After driving a Goshawk and then handling a 40/50, I feel that every ounce of weight on the front wheels should be removed, or pushed back, such as spare wheel etc. *Referring to the Bentley, the smaller model last year was extremely bad when fitted with balloon tyres. Really we do not know quite enough to definitely say what is best to do, but in a few days we hope to be in a better position. R.{Sir Henry Royce} | ||