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 suspension performance, ride quality, and buffer clearances after testing.
| Identifier | ExFiles\Box 83\1\ scan0250 | |
| Date | 10th October 1936 guessed | |
| ( II ) at the rear. The Roll-rod was disconnected and the harshness reduced. With a full load, the car rolled and oversteered. The rear axle frequently bottomed on the buffers. Investigation revealed that the rear damper initial poundage was only 32 lbs. This was increased to 60 lbs, and with 34 lbs/sq." pressure in the rear tyres, the rolling and oversteering was completely overcome, with or without the roll-rod in action. The excessive float and throw-up at the rear was also overcome, but the front continued to be harsh, particularly with the roll-rod connected. The front damper initial poundage was therefore reduced from 60 lbs to 40 lbs. The front suspension was then good without the roll-rod but still slightly harsh when it was connected up. There was an increase in float at the rear after the front damper poundage was reduced, but this was only apparent at high speeds over wavy surfaces. On rough roads and cobbles, the ride was very steady at all speeds and there was no excessive throw-up over humps, but the rear axle still hit the buffers too frequently. The car was equally easy to drive with or without the roll-rod on all kinds of roads. It gave increased rigidity to the control at the expense of adding harshness to the ride. We preferred the car with it disconnected. The results obtained were arrived at by careful attention to damper setting and tyre pressures, and could not be further improved by the roll-rod. Also when rolling was experienced due to insufficient rear damper poundage, the roll-rod did not overcome it. On this car it is quite unnecessary and is best dispensed with. Although a good all round ride was obtained, there was a knobbliness at low speeds which could not be overcome by reducing the damping. This has been accepted as a character-istic of the thick leaf springs. The worst feature was the hitting of the buffers, even with light load, and would not be tolerated. Increased axle movement and buffer clearances are essential to the success of the lower rated springs. Buffer Clearances. N.S.F. O.S.F. N.S.R. O.S.R. 4,500 Miles 1.5/16 1.1/4 2. 2. 16,920 Miles 1.1/8 1.1/8 1.3/4 2. Difference 3/16 1/8 1/4 0. No damper knocks were heard during the mileage, and loss of oil from the dampers was negligible. DASHBRACKETS & FOOTBOARDS. LOP FB.1888 LeC.4630. 4484 90 R.R.Scheme 873. Existing, complete to above LOP & Schemes incorporating:- Noise Insulated Dash. FB.2258 Dashboard. LeC.4907 Petrol Pump on Dash. The dashboard insulation gave a high degree of [Handwritten note in left margin]: Les G.W.H. Standardisation of thin leaf springs completed We now give By instruction axle poundage and damper loads. | ||