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).
Effects of shackling the rear spring on vehicle riding quality.
| Identifier | ExFiles\Box 43\2\ Scan136 | |
| Date | 28th April 1926 | |
| Oy2-E-42826 X3900 April 28, 1926 To: Mr. Southern cc Mr. Hives Mr. Nadin Mr. Beaver Mr. Hulley Mr. Caswell From: Mr. Olley Re Springing Replying to yours of April 26th I cannot understand why shackling the spring at the rear should produce any improvement in riding. We have only our own observations on 12-MC (without measuring instruments) to prove that it does. I thought it advisable to cable England about it however, because although we have only one car to work on, we all agree that on this car Silver-Ghost riding quality has nearly been reached and that the steering and general handling no longer have the original undesirable features. England are working at the job even harder than we are and it seems best to give them the benefit of our results as quickly as possible even though they may be based on insufficient evidence. When you are up here I wish you would take the car out for a long run, and let us get your impressions. As you say it is easy to see that pulling the axle along might be better than pushing it through a spring, but when you look at the actual figures it is difficult to find why it should be so. For example, what about the millions of Hotchkiss drive cars that push through the springs? (Although I have heard cases of Hotchkiss cars where improvement has been made by shackling the rear spring in the front.) The thrust from the rear wheels on a large Hotchkiss drive car weighing say 2000 lbs. on the rear axle may be 400 lbs. in high gear, whereas the tire friction on 12-MC cannot be much more than 40 lbs. on both wheels, i.e. 20 lbs. compression in the rear half of each spring when shackled at the front. | ||