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 tests comparing Michelin and Dunlop tyres.
| Identifier | ExFiles\Box 29\1\ Scan350 | |
| Date | 26th October 1928 | |
| +457 To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/Rn.{Mr Robinson} c. to BJ. Wor.{Arthur Wormald - General Works Manager} c. to DA.{Bernard Day - Chassis Design} E.{Mr Elliott - Chief Engineer} c. to BY.{R.W. Bailey - Chief Engineer} Hs{Lord Ernest Hives - Chair}/Rn{Mr Robinson}7/LG26.10.28. HIGH SPEED WOBBLES. We have recently been carrying out tests on Michelin tyres. These tyres are called 17 X 50 and are fitted on special rims. Their rolling circumference is 99.5". Our standard tyre is 103.25". We therefore imagine that the Michelin tyre will correspond closely with the Dunlop tyre on 20" rims. In our tests we compared : (1) Standard triple stud Dunlop 6.75" tyre 21" rims. (2) Standard silent tread Dunlop 6.75" 21" rims. (3) Michelin 17 X 50 Bibendum. Our tests were to determine the steering qualities of these tyres at high speeds and their relative tendency to high speed wobble. The results confirmed our previous experience. (a) The silent tread tyres, being the least non-skid gave the best steering but were not very different from (b) The triple stud Dunlop the next best. (c) The Michelin tyres were definitely inferior to the other two and produced a very restive steering at high speeds which perpetually 'nibbled' at the drivers hand. We therefore consider that when we come to the smaller wheels on SS.{S. Smith} we shall not have an easy time with our steering. We are therefore continuously working on the high speed wobble problem. contd :- | ||