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).
Technical document detailing the causes and characteristics of low-speed wobble in vehicles.
| Identifier | ExFiles\Box 170\3\ img037 | |
| Date | 14th July 1933 guessed | |
| -8- Low speed Wobble. This occurs without any appreciable tramping of the wheels, and is an older trouble dating long before front brakes. It was less clearly understood than shimmy principally because the amount of power consumed was small, so that it could be easily damped out by applying a little friction to the kingpins, but as the mass rotating about the kingpin has increased (front brakes, Dubonnet suspension etc) low speed wobble became gradually more and more difficult to control. With the very first Dubonnet job on SLA low speed wobble was a noticeable characteristic, and it seemed to be a feature of cars in which the moment of inertia about the kingpins was high. The characteristics of an independent front end which tend to make the steering effort greater than on an axle (leaning of the wheels and consequent greater slip angles) make it less desirable to damp out the wobble tendency by friction, and more necessary to seek a basic cure if it is possible to find one. The first 'Detonation' of the wobble may be the rocking of the car by a road bump, a horizontal shock to one wheel as on a grade crossing, Light braking with eccentric drums etc. | ||