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 analysis of wheel wobble, suspension characteristics, and spring deflection, with comparisons to Cadillac.
| Identifier | ExFiles\Box 173\1\ img109 | |
| Date | 26th January 1934 | |
| -2- (b) The same mass rotating with the wheel promotes a low speed wobble. The latter statement I cannot understand since the low speed wobble, as we know it, derives all its energy from the tyre contact and has such a low frequency that one would not expect it to be affected by a small quantity of inertia. Either it is very convincing. (3) They find the best compromise for the Cadillac to be: King pin angle - 3.5° Wheel angle - 1.5° and would prefer less Out of centre point - 4.5° Plain journal bearings in pivots Ball thrusts in pivots Threaded shackles for arms. (4) The lengths of the parallel arms should be approximately conversely as their distance from the ground: Cadillac top arm 10" long Bottom arm 2." long (5) As long as the front springs have an initial deflection of over 6" a good high speed ride will result, but to get a good low speed ride as well the front spring deflection must be greater than that of the rear springs. On the Cadillac, the rear spring initial deflection is 6", the front spring 9". (6) The steering they are using with the independent wheel suspension is the complete Marles. (7) The measured torsional frame frequency at which they aim is 800 a min. I do not understand how they measure this, as by our method it would be impossibly high. However, I will find out in Detroit. (8) Independent springing has added 5% to the cost of the Chevrolet, but on the Cadillac the increase in cost will be negligible. | ||