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).
Extract regarding complaints of knocking in the transmission, its causes related to leaf springs and road conditions, and a suggestion to fit shock dampers.
| Identifier | ExFiles\Box 32\1\ Scan005 | |
| Date | 8th June 1921 | |
| X1494 Extract from R10/G8.6.21. X.3614 - RE U.S.A. COMPLAINTS. X.1511 X.2628. KNOCKING IN TRANSMISSION. X.1494. As is well known, there are two causes of the knocking in the transmission; one is the uneven roads vigorously throwing the axle up and down relative to the body. This causes speed variation in the transmission shaft, and hence a knock. It will be remembered that even with thin leaved springs the damping of the rear of the car is insufficient until the springs become dry and somewhat rusted. They have then considerably more friction between the leaves, and therefore damping effect than a new car, or in one in which the springs have been greased. It was for this reason we decided to change from the thick leaved springs to the thin leaved springs. This is ancient history, but I mention it because I would like to point out that you cannot expect new or freshly delivered cars to be much better than those with the springs having thick leaves. If, therefore, you find that the thin leaved springs do not obviate the trouble of unsteadiness in the rear of the car on your peculiar roads then I suggest that the next thing to do is to fit shock dampers or Gabriel snubbers, either of which will tend to steady the body, and so make the riding on certain roads more comfortable, and at the same time stop to some extent the transmission knock which arises from this speed variation. Contd | ||