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).
Comparing the tyre removal features of Michelin and Dunlop wheels and proposing a new two-depression rim design.
| Identifier | ExFiles\Box 45\2\ Scan040 | |
| Date | 27th October 1931 | |
| Hs.{Lord Ernest Hives - Chair} from E.{Mr Elliott - Chief Engineer} X4050 E1/M31.10.27. RE. MICHELIN & DUNLOP WHEELS. X.987 X.3725 X.4050 X.3482 We take it that the Michelin wheel has an eccentric depression which allows the tyre to be removed in one place only, hence this tyre is not so liable to come off as the Dunlop, which latter can be removed in an infinite number of positions. It occurs to us that Dunlops would be at liberty to make a wheel with two depressions opposite to each other which would allow the tyre to be removed in two places only. Compared with infinity this is still nearly as good as the Michelin. A further step would be to make these two depressions of half the Michelin depth so that the cover would have to be removed at a point mid-way between the two depressions and by more distortion than usual, probably rendering the tyre still more secure. The two-depression rim has the advantage of being balanced. E.{Mr Elliott - Chief Engineer} | ||