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).
Test report detailing the effects of modifying tyre pressures and front springs on ride comfort.
| Identifier | WestWitteringFiles\S\September1928-October1928\ Scan019 | |
| Date | 6th September 1928 guessed | |
| contd :- -3- Briefly, if you hold either end of the car to the axles at this speed and leave the other end free, it appears that the end that is held acts as a pivot and anyone seated on the pivot suffers the least discomfort. We confirmed this result by reducing the front shock absorber loading to half standard and repeating Test 1. The riding in the rear seats was measureably improved. TYRE PRESSURES. ============= The effect of reduced tyre pressures varies according to the shock absorbers employed. In every case, however we found that a reduction in tyre pressure, whether on the front or the rear, improved the low speed riding. As a measure of the relative importance of tyre pressure and shock absorbers we found that if we took the car in a standard condition (Test 1), lowering the tyre pressures by 10 lbs/sq.in. was just equivalent to disconnecting the front shock absorbers (Test 3.) and leaving the tyre pressure at 40 - 35 lbs/sq.in. FRONT SPRINGS. ============= We fitted the American type of front spring and compared it with the standard type. We carried out three tests on each type of front spring. The American spring has 3.687" initial deflection against our 3.1" i.e., 19% lower rating. (5) Car with standard tyre pressure and shock damper loading. Rear buffer clearance 4". (6) As (5) but with tyre pressure at 25 lbs/sq.in. rear, 35 lbs/sq.in front. (7) As (6) but with front dampers disconnected. Our results shewed us :- contd :- | ||