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).
Letter discussing rear spring specifications, buffer clearance, and vehicle weights.
| Identifier | ExFiles\Box 16\7\ Scan306 | |
| Date | 17th October 1930 | |
| Rolls-Royce (America) Inc., Springfield, Mass., U. S. A.{Mr Adams} 47410 To OY. From Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}6/MJ.17.10.30. With reference to your letter of Oct.1st. We have been through a certain amount of tribulation owing to springing cars on the light side due to an endeavour to give the softest possible ride. We find, however, that the semi-eliptic rear spring definitely seems to have freer action than the cantilever, and in consequence we have to leave slightly more buffer clearance to prevent striking through. We have established that the best buffer clearance for average running is between 4" and 4 1/2" and that any cars with less than 4" buffer clearance will sooner or later strike through. The average weight of our experimental chosed cars, which are both Cabriolet de Ville and saloon, is 5400 lbs. with one spare wheel carried at the back which comes out very closely to your estimated weights of 5450 for this type of body. To give 4" buffer clearance with four passengers we fit 1375 to 1400 rear springs. We think that if you fit 1300 rear springs you will certainly be too light. With regard to the front spring we think that you can make more use of the 1100 lbs. | ||