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 of wheel wobble and basic alterations to prevent its occurrence.
| Identifier | ExFiles\Box 178\1\ img118 | |
| Date | 13th July 1926 guessed | |
| - 19 - force in the wheel is exactly what is required to set it going. Again, in the manufacture of tyres, unavoidable errors occur so that even if the wheel is balanced, one portion of the tread deflects more than another, producing the effect of running on a slightly oval wheel. This acts in exactly the same manner as an out of balance force. We have actually proved by selecting two bad tyres and running them against two good ones, all balanced, that this discrepancy in manufacture can alone cause wobbles. The following addition items aggravate wobbles:- 1. Semi-reversible steerings and rigid side steering tubes or very strong side steering tube springs. 2. Large section tyres with broad or good non-skid treads. 3. Light undamped front springs. 4. Too much wheel gather or toe-in. Anything above 1/8" is undesirable. 5. Too much longitudinal inclination of the pivots or castoring angle. 6. Under-inflated tyres. 7. Any play in the ball ends or mechanism of the steering. This includes spring shackles, etc. (c) Basic alterations to prevent occurrence. 1. Reduction in weight of front axle and particularly in weights at the extremity of the axle. 2. Fitting the maximum strength of road springs for comfort as widely spaced on the axle as possible. 3. Fitting a device to put up the criss cross period of the axle while leaving its parallel period unaffected. (Something similar to an anti-rolling device). 4. Fitting really good shock absorbers as near the wheels as possible to have the maximum restraining influence on criss cross motion. Preferably hydraulic type. contd. | ||