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 on front spring deflection, ratings, and ride quality modifications.
| Identifier | ExFiles\Box 43\2\ Scan088 | |
| Date | 18th December 1925 | |
| Oy4-E-121825 -5- December 18, 1925. 7. (cont'd.{John DeLooze - Company Secretary}) Right front Stamped "1150" Left front Stamped "1100" Flat (App. 2.600 deflection) 910 lbs. 895 lbs. .5 negative (App. 3.100 deflection) 1090 " 1070 " .9 negative (App. 3.500 deflection) 1230 " 1200 " Rating 350 lbs./in. 345 lbs./in. (All readings are average of up and down). Under this car we should use two 1200 lb. springs (rating 345 lbs./in.). It was evident therefore that the car was not appreciably stiffer-sprung in front than normal run of Springfield cars. Presumably in springing the car Derby did not allow for as much additional weight in mudguards etc. as we actually put on. The explanation of the front riding was therefore not in the spring ratings. However, to test the performance of the car with very soft front springs the 7th plate was removed from the right front spring and the springs interchanged from left to right. This gave us Right front Left front 3 1/2" deflection 1200 1125 Average front springing 1162. The car now bumped in front again and tendency to steering wobble was more pronounced. There was some improvement in riding. 8. All front brake gear was removed from the front axle. Steering appeared easier, and general impression of harshness in the front seat was improved, but riding quality especially in the rear was not improved. It was suggested that possibly the wider axle pad used with front brakes, by stiffening the front springs, might be responsible for the front riding. 9. Two pads were therefore made representing our present front axle and the wider front axle used with front brakes. | ||