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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).
Technical report discussing car instability, steering wobble, and solutions involving friction in the pivots and springs.

Identifier  ExFiles\Box 80\1\  scan0107
Date  9th September 1920
  
R.R. 235A (100 T) (S.H 159, 11-8-20) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2200

Contd. -4- Hs{Lord Ernest Hives - Chair}3/LG9.9.20.

for causing the car to be unstable but we never made Mr. Salamanca satisfied until we leant the pivots back slightly more than they were originally. There is no doubt that increase backwards lean on the pivot does make the steering more stable. A very good proof of this is the fact that if one makes a car so that the pivots lean forwards the least amount, the car is positively dangerous to drive. With our present cars we check the lean on the pivots with the frame level, this means that when the car is lightly loaded or on the re-bound of the springs, the pivots have practically no backward lean and under that condition with the car travelling fast it does not feel safe.
We have also received other complaints on cars of the constant oscillation of the steering wheel when going over a rough road. (This must not be confused with the low speed steering wobbles). This fault takes place at all speeds. It was in order to overcome this particular trouble that Mr. Royce suggested that friction should be tried in the steering pivots and also the springs in the side steering rod should be made so that instead of having two balanced springs, we have one spring at each end which sets a definite pressure on the ball. The springs are arranged so that they give flexibility either way. The friction is applied by altering the thrust race in the pivot. We grind out the race for the balls and make it flat, we insert a fibre washer which makes up the thickness of the balls and fix a flat washer on the top. We

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