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).
Letter regarding the testing of Michelin 'Pilote' tyres and a proposal for further tests with newly manufactured tyres and wheels.
| Identifier | ExFiles\Box 146\1\ scan0282 | |
| Date | 14th June 1938 | |
| 1245 To "Rm{William Robotham - Chief Engineer}" DERBY PARIS Sr2I/Dn.14.6.38 Dear "Rm{William Robotham - Chief Engineer}", Re- Michelin "Pilote" Tyres I received the very interesting information you sent me some time ago on this subject, which I had translated and forwarded same to Mr. Marcel Michelin. We had a conversation about this a few days ago, and Mr. Michelin thanks you first of all for trying his tyres and wheels, also for the information given, which has been found very interesting. He points out however, that the tyres he gave you were the only ones available at the time and compared with the 5.50x18 they would not stand the same load. In other words the 5.50x18 is a tyre which is capable of standing a considerably higher load than the tyres tested. They are sufficiently interested, however, in this matter to continue the tests, and they propose "knocking up" another set of wheels, to which they would fit a new tyre they have just manufactured that is just a little undersize as far as the 5.50 x 18 is concerned, and would have the following characteristics : The diameter not under load would be 744 m/m " circonférence de roulement is 2 m 200 This, as you will appreciate, is but a little under 5.50 x 18, which has a diametre not under load of 765 m/m , and a circonférence de roulement of 2 m 268. If you are sufficiently interesred, and I hope you will be, within the next month the Michelin Experimental Department will "knock up"these wheels, and I will have them sent out to you. Incidentally, Mr. Marcel Michelin, who is a very nice man, will probably, when these wheels are ready, ask to be invited to the Works with one or two of his Engineers, to be present at a demonstration of your methods of finding out all about tyres if, of course, you are willing. In making your decision on this matter, please do not overlook the fact that there are three Bentley cars in the Michelin family. Sr. | ||