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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).
Continued report on suspension performance, comparing shock dampers, tyre pressures, and spring configurations on various car models.

Identifier  WestWitteringFiles\O\2April1926-June1926\  Scan020
Date  1st April 1926 guessed
  
contd :-
-2-
car with ball bearings between the spring leaves. While a little friction does not make it very much worse at this speed, actually the optimum riding condition is with no shock dampers. Of course under these circumstances the riding at higher speeds on bad roads becomes impossible.
(b) The hydraulic shock dampers when fitted on the front do not make the riding of the car appreciably worse. Actually, though we can clearly measure the effect of putting 25 lbs. friction on the rear shock dampers, we can only just detect the difference between having unrestrained front springs with no internal friction (i.e. ball bearings between the leaves) and fitting the hydraulic dampers.
(c) Tyre pressures make a very real difference to the complaint. Lowering the tyre pressures from 45 lbs/sq.in. to 30 lbs/sq.in. alleviates the trouble to a greater extent than eliminating the internal friction of the springs.
(d) The 20 HP. is a very much better sprung car at the rear than any 40/50 HP. When we have done all we know of to the Phantom including 20% weaker front springs, ball bearings between the leaves front and rear, Silver Ghost pre-front wheel brake axle, no shock dampers, and tyre pressures at 25 lbs/sq.in. and 30 lbs/sq.in., we are still slightly inferior to the standard 20 HP. -(i.e. tyre pressures 40/45 lbs/sq.in., rear shock dampers 45 lbs.) for riding comfort under the stipulated conditions.
(e) A 20% reduction in the strength of the front springs does not turn the 40/50 HP. from a well-sprung car into a badly sprung car. Our present estimate is that the contd :-
  
  


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