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).
Technical memorandum discussing clutch pedal pressures on the Phantom II and 25HP models.
| Identifier | ExFiles\Box 13\7\ 07-page132 | |
| Date | 5th July 1932 | |
| S. From Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls} c. to SS.{S. Smith} Mor. c. to S. De. c. to SV. HS{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls}11/MA.5.7.32. CLUTCHES P.II AND 25HP. We are sending you this information about clutches as we consider that the pedal pressure on our cars has become unpleasantly large. This of course is due to the fact that we have continually increased the strength of the clutch springs to contend with higher engine torque. Only in one case, the "U" series 25HP, have we adjusted the leverage to reduce the pressure. The figures for the pedal pressures fully to depress the pedal are :- 25HP "U" Series 38 lbs. Early P.II. 38 lbs. Present Std P.II. N.3 Series. R.H. 45 lbs. L.H. 80 lbs. The reason for the pressure being greater on the L.H. chassis is that the angular positions of the operating lever gives a greater clutch separation, according to the drawing of .857 against .679 for the R.H. chassis. We propose altering the pedal on the R.H. chassis to give the increased separation this being important on cars that have no clutch brake (with synchromesh gearbox). 19-SX car has a maximum engine torque of 18% greater than the Std: P.II. We have had to increase the clutch springs by a similar amount to prevent slipping. With these springs and the new pedal about 57 lbs will be required to put out the clutch. | ||