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).
Wheel and tire standards, discussing compatibility and standardization between Dunlop and American manufacturers.
| Identifier | ExFiles\Box 19\4\ Scan062 | |
| Date | 24th June 1930 guessed | |
| -2- (e) Anticipate no real replacement difficulty in states since Dunlop, Firestone, Goodyear and Goodrich are producing these in their European factories and probably (on an experimental scale) in America. (The whole recommendation, however, hinges on Mr.Ross establishing that no replacement difficulty will actually exist.) (2) (a) The 20" wheel is nearing its end in the States and being replaced by 19" and 18". (b) The 19" wheel gives better appearance and slightly better steering lock. Not quite so good mileage, but industry generally appears to have decided to ignore this, trusting tire makers to "rise to the occasion". We have proved that the road clearance with the 19" wheel is not too small to be acceptable. (c) Discussion on wellbase rims between Dunlops and the American makers has concerned - width between flanges - Dunlops narrower, American wider. Height of flange - Dunlops deeper, America shallower. Width and depth of well - Dunlops less, America more. Dunlops have agreed to accept the American standards in width and height, but will not agree to the large well because unsafe if tires deflated at speed. In our size this means they agree to 4" between flanges instead of 3.750 and to .844 flange height instead of .875. They are preparing to alter their rim manufacture to correspond. They believe agreement (which will form the basis of a "world standard") will soon be reached. (d) They believe that test by Derby of the 19 x 7 well-base tire and 4" wide rim is the desirable next step with a view to ultimate standardisation on the large cars both here and in America. (e) Tires made for wellbase rims will be usable on straight side rims. The difficulty has occurred through American makers trying to do the opposite thing, that is, produce a well base rim which would take a straight side tire of present type or a slight modification thereof. This led to - cont'd.{John DeLooze - Company Secretary} | ||