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, wheel balancing schemes, and potential solutions.
| Identifier | ExFiles\Box 28\4\ Scan322 | |
| Date | 22th August 1925 | |
| To CJ. from R.{Sir Henry Royce} c. to BY.{R.W. Bailey - Chief Engineer} Hs.{Lord Ernest Hives - Chair} 457 R1/M22. 8. 25. X.457 X.8430 HIGH SPEED STEERING WOBBLES+ So far we have not much hope of modifying the chassis or steering so that this phenomenon cannot happen. It seems almost beyond our control because should we add enough friction to prevent an out-of-balance of 1 lb. growing into a wobble we could not steer the car satisfactorily and the only hope we have is in the hydraulic damper which we have instructed Derby to test, and which we have designed as a permanent piece for the chassis. We believe that all other chassis of similar weight and speed have the same tendency. Regarding the minor phenomenon of the driver feeling the road shocks, and the prevention of low speed wobbles, we believe we have met these by the combination of a slightly slower steering, a larger dia. of worm, and the damper pendulum lever. We ought to prepare at once for fitting these modifications, pendulum further road experience. Regarding the present chassis I think we are bound to issue these, and it appears that we are forced to use Dunlop tyres, in spite of their practice of constructing the inner tube by a scheme which naturally gives an out of balance. At the same time I feel as though we ought to threaten them that we must seek another make of tyre if they insist upon sending out a design which produces an avoidable out of balance. I have received BY's memo. on the subject, and I think of the schemes suggested for balancing, we ought to use No.2., i.e., the three studs scheme, which will make it easy for anyone, at any time, to adjust the balance of the wheel, fortunately this being very conveniently done in the case of the front wheels, which are the important ones. The subject must be dealt with in the instruction book. (1) You will see therefore that for immediate chassis we can only suggest that balloon tyres should be avoided for the front wheels, that the tyre pressure should be kept as directed at 50 lbs. per sq.in. or more, and that the front shock dampers shall be kept in an effective condition. (2) Future chassis can have slightly slower steering, damped pendulum lever, and (1). (3) Still more future chassis can have contd:- | ||