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).
Vehicle handling issues related to tyres and shock absorber settings.
| Identifier | ExFiles\Box 28\1\ Scan130 | |
| Date | 18th July 1928 guessed | |
| contd :- -2- (8) We do not believe that you will be able to use tyres on the front at 35 lbs/sq.in. without danger of 'shimmy' or 'tramp' unless you make the front of the car ride harshly by increasing the shock absorber setting. It is however just possible that your American tyres are better for absence of wobbles than our British tyres. For instance, we find that Rapsons with the deflector inner tubes are not prone to high speed wobbles; they have other disadvantages however as they groan at low speeds. Our next move is to try your dampers on the road, but we feel that we shall be up against the fundamental difficulty of car control v.{VIENNA} soft riding. You may have hit on a better compromise than our standard, but until we get damping which is automatically variable with the road speed of the car, we feel that the best we can do is to have a shock absorber which can be adjusted to suit the speed at which the customer habitually drives. You will probably be somewhat mystified by the diagrams of the standard damper with the air vent blocked up. So are we. Why the minimum pressure in the whole damper should rise more on the high pressure than the low pressure side when both are connected by the high pressure passage is more than we can say. Also, why the pressure at which the low pressure valve opens is not equal to the spring pressure plus the pressure on the head of the valve. We are certain that the indicator is right, it is our knowledge of hydraulics which is faulty we can only presume. We should be interested to have your observations. He/Pm. | ||