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).
Ongoing tyre testing for the Corniche model, comparing Dunlop and Avon tyres.
| Identifier | ExFiles\Box 97\3\ scan0193 | |
| Date | 30th July 1939 | |
| 4009 To. Rm.{William Robotham - Chief Engineer} c.c. Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls} c.c. Rm{William Robotham - Chief Engineer}/FJH.{Fred J. Hardy - Chief Dev. Engineer} Châteauroux. 3/30.7.39. I4.B.V.- Corniche. TYRES. Further to our memo Châteauroux 3/28.7.39. we are getting some rather bewildering tyre results, so we do not want you to make any final decisions based on our tests to date. We think that provision in the spare wheel compartment and rear wheel covers for 7.00 tyres is a wise precaution, but we do not want to definitely say that the larger tyres are essential until we have more data. Yesterday, we tried the 6.50-16 Dunlop Rayon tyres on 4.1/2" rims and were very surprised to find that they were even better for directional stability than the 7.00-16, in fact absolutely free from wandering. They slipped a little more on corners, but the steering was much lighter and free from reactions and the over-geared feeling had gone. The car was not quite so steady driving right in the gutter at maximum speed, but taken all round it was more acceptable with these 6.50 Dunlops than any tyres tried before. We then fitted a set of partly used Avons 6.50 -16 light tread tyres and found that the darting about in front did not occur as originally complained of. We are next going to try a set of new 6.50-16 Avons. We will let you know the results to-morrow. Our present line of thought is the trouble only occurs when there is a wind blowing. If we find this to be the case, we shall have to repeat all the tests on windy days only. We want to keep you informed up-to-date of our work, but these latest tests show that the results up to the present are anything but final. --------- Rm{William Robotham - Chief Engineer}/IMW.{Ivan M. Waller - Head of Chateauroux} Jwaller | ||