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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).
Comparison of standard versus stiffer road springs and their performance characteristics under load.

Identifier  ExFiles\Box 17\1\  Scan086
Date  16th June 1932
  
Y7410
Hd{Mr Hayward/Mr Huddy}/SB.{Mr Bull/Mr Bannister} From HS{Lord Ernest Hives - Chair}/Rn.{Mr Robinson}
c. to AY.
c. to SP.{Mr Spinney}
c. to MX.{John H Maddocks - Chief Proving Officer}
c. to Ms.
Y7120.
Hs{Lord Ernest Hives - Chair}/Rn.{Mr Robinson}1/MA.16. 6. 32.

Re. STIFFER ROAD SPRINGS P.II.

Referring to Hd{Mr Hayward/Mr Huddy}/SB.{Mr Bull/Mr Bannister}10/AGH.7.6.32.

The comparison made is not fair because it assumes that a car would have 1350 lb springs fitted if sprung normally and 1250 if sprung continentally which is incorrect. Taking the car in each case with 1350 lbs springs we get :-

Standard. Stiffer.
Poundage 1350 1350
Rate 154lbs/1" 220lbs/1"
Buffer Clce. 3.800 2.520
Increase in static load to buffers 590 555

However, our experience is that "crashing" occurs when the buffer is compressed 1" and the driver does not know when the axle "flicks" the buffers. The continental springs were designed on this assumption, and the "crashing" point taken as 4.850 neg camber. The relative immunity from crashing then becomes :-

Standard. Stiffer.
Rate 154lbs/1" 220lbs/1"
Deflection from normal riding to "crashing" 4.8 2.750
Increase in "static" load to produce this result 790 lbs 620 lbs
  
  


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