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).
Spring specifications and performance characteristics for various vehicle body types.
| Identifier | ExFiles\Box 43\2\ Scan044 | |
| Date | 10th June 1922 | |
| Oyl - G 10622 -4- June 10, 1922 unloaded position of the springs and the springs are properly lubricated, it will have an actual frequency of 70 to 80 complete bounces a minute depending on the condition of lubrication. If the springs are allowed to dry out the frequency rises above 90 and flinging makes its appearance at the same time. On the roadster bodies it would be necessary to use 1500 and 1600 lb. springs at the rear to satisfy the above condition, and this would give us another trouble, we find - namely, the bouncing of the unsprung axle between the spring of the tires and the rear springs. To avoid this we put a 250 lb. block of cast iron in the extreme rear end of the roadsters only and use 1600 and 1700 lb. springs. This seems brutal, but it has been done before and is effective. As a result we now have standardized the following springs - 4 fronts and 5 rears. (Remember that our springs are all within 15 lbs. of their rated load.) Type Av.Body Wt. Inc.Wings,Lamps,etc. L.Front R.Front L.Rear R.Front (Roadster (Spring for 3 1065 1050 1100 1600 1700 (5-Touring (Spring for 4 1075 1050 1100 1700 1600 (Enc. Drive Cabriolet Spring for 5 1245 1100 1150 1800 1900 (7-Touring (Spring for 5 1330 1100 1150 1800 1900 (Town Brougham Spring for 4 1378 1100 1150 1800 1900 (3/4 Cabriolet (Spring for 4 1395 1100 1150 1800 1900 (Limousine (Spring for 5 1444 1150 1200 1900 2000 (Sedan Spring for 5 1462 1150 1200 1900 2000 (Cabriolet (Spring for 5 1502 1150 1200 1900 2000 (Enc. Drive (Limousine (Spring for 5 1503 1150 1200 1900 2000 | ||