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).
Analysis of wheel fight, its causes related to steering gear, chassis stiffness, and testing methods.
Identifier | ExFiles\Box 170\3\ img062 | |
Date | 15th July 1935 guessed | |
-2- on a bonnet such as m.p.h. on wishbone jobs. The range through which it may be produced depends on conditions (particularly castor) and may range from 1 m.p.h. to either side of whatever speed. whilst much worse on wishbone or conventional jobs a bonnet job where it can be made to occur it appears to be closed to about 40 m.p.h. Steering Gear. Really severe wheel fight we believe is always of the low frequency type which approaches low speed wobble. Or example, if for any reason such as neglect, or backlash in steering, a car develops wheel fight and nothing is done to correct it, it will eventually develop definite trouble which may build up even on dead smooth roads. It follows that difference in wheel fight characteristics between steering gears, which has hitherto been considered a matter of reversibility of the gear, may be rather a question of the stiffness between the pitman arm and the steering wheel. In other words, if the gear is mounted on a base plate with the end of the steering wheel shaft located solid, and deflection takes place at the pitman arm ball, the softer gear will almost always be worse for wheel fight than the stiffer gear. Stiffness of the mounting brackets on the chassis frame enter into this overall stiffness in actual use of the car. Not only this but we believe this stiffness is "critical". i.e. an increase in stiffness may in certain conditions just turn the corner, and give complete freedom from wheel fight. Testing. We have just done a lot of testing on the road and on our "wobble-o-meter" driving to show exactly what wheel fight, wobble etc, really are. By putting the front wheels on dead smooth drums, out of centre of the drums, to give a counter to effect, and by then detonating the cycle by means of snatching the steering wheel, or by means of a bar projecting forward from one steering | ||