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 from Dunlop Rubber Co. Ltd. regarding the market dominance of 21-inch rims for low-pressure tyres.
| Identifier | ExFiles\Box 42\1\ Scan019 | |
| Date | 5th November 1925 | |
| C O P Y. The Dunlop Rubber Co. Ltd., Fort Dunlop, Erdington, Birmingham. 5th. Nov. 1925. Messrs. Rolls-Royce Ltd., Derby. For the attention of Mr. W.A. Robotham. Dear Sirs, We are in receipt of yours of the 31st. ult. and in reply would say that the 21" dia. rim is now by far the most important diameter for low pressure tyres - in fact, we have adopted the 21" rim as the standard diameter for all cars on well base rims, other than light cars, for which the rim diameter is 19". You may be interested to know that the last return of rim production by the Tire and Rim Association of America gives the following percentages :- 20" rims ......... 27.2% 21" " ......... 72.3% 22" " ......... 0.5% from which you will see the preponderating importance of this diameter. With regard to the production of tyres to fit our well base rims - We would say that the Michelin Co. show several sizes of tyres in their present lists and we believe they are producing others. We have, however, arranged for the production of all sizes of tyres to fit our well base rims at our Factories in France and Germany, and both Goodyear and Goodrich Cos. are producing similar tyres. Many other British and American manufacturers are also engaged in producing such tyres and we think you need be under no anxiety as to the obtaining of replacements. We shall, of course, be only too glad to render you any assistance in this matter in any specific cases on hearing from you. Yours faithfully, FOR THE DUNLOP RUBBER CO. (Sgd.) W.H. Paull. | ||