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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).
High-speed wobble (shimmy) in cars, detailing experiments and observations.

Identifier  ExFiles\Box 29\1\  Scan325
Date  14th March 1928 guessed
  
contd :- -2-

In one of our experiments a high speed wobble was so powerful that it absorbed 20 HP. at 65 m.p.h. and at that speed each wheel in turn left the road for 9 ft.

THE AUTHOR :

Not vertically I hope!

MR. ROBOTHAM :

No, horizontally. I do not know how high vertically, but some people who were cutting a hedge a long distance away saw us approaching and ran away across the fields.

With regard to cars with independently sprung wheels. I have tested a Lancia so fitted but was able to make the car high speed wobble. In this case there was no front axle. In full wobble the bonnet opened 1" or so at the back each side as the frame distorted.

Naturally, we went out of our way to make this car wobble; Lancias normally are not subject to this sort of thing.

Again the Cottin des Gouttes has duplicated pendulum levers and side steering tubes but can be made to high speed wobble without difficulty. So that it cannot be said emphatically that either independent wheel suspension or duplicate steering gear are a cure for 'shimmy'.

We have tried all sorts of things to prevent high speed wobble but there is no royal cure.

Undoubtedly one essential thing which Mr. Lanchester points out is to have balanced wheels - but tyre size, pressure, tread, peripheral weight, contd :-
  
  


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