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 causes and contributing factors of high-speed steering wobble and front axle vibration.
| Identifier | ExFiles\Box 67\3\ scan0260 | |
| Date | 12th June 1925 | |
| R.R. 493A (50 H) (D.D. 31. 12-6-25) J.H.D. EXPERIMENTAL REPORT. -2- Expl. No. REF:He/Rm{William Robotham - Chief Engineer}2/103.9.25. point, drastic alteration in the present standard design of the front of the car will be necessary to secure complete immunity from high speed wobbles. A high speed steering wobble is due to a criss cross vibration of the front axle. Every front axle has a period of its own depending on its mass, the distribution thereof, and the strength of the springs with their location and loading. If a front axle could be made to have a very high period of criss cross vibration, a high speed wobble would not occur within the range of a normal car's speed. The tyre affects the period of vibration, a low pressure tyre reduces the period. The nature of the tyre affects the period, a tyre with a lot of internal friction such as a canvas cover, will damp the vibration. There has recently been a wide demand for :- (a) Front wheel brakes. (b) Cord tyres. (c) Low pressure tyres - every one of these factors affects criss cross axle vibration adversely from the point of view of high speed wobbles. Without radical departure from present practice, we can only attack :- (1) Weight of the axle. (2) Weight at the end of the axle. (3) Distance apart of the springs and their strength. In order to bring the criss cross period of the axle back in status quo. It will be apparent to everyone that the amount of alteration which can be made in the items mentioned is practically negligible, and will certainly not counteract the aggravating contd:- | ||