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 United States Rubber Company responding to questions about tire and rim standards.
| Identifier | ExFiles\Box 19\3\ Scan141 | |
| Date | 11th January 1930 | |
| COPY UNITED STATES RUBBER COMPANY Detroit, Mich. January 11, 1930. Mr. Maurice Olley, Chief Engineer Chassis Div. Rolls Royce of America, Inc. Springfield, Mass. Dear Mr. Olley: Your letter of December 16th to the S.A.E. New York, has been forwarded to us by Mr. A.J. Underwood. The delay in answering has been due to my absence at the Automobile Show in New York. In answer to question 1 in your letter, we believe the 7.00-20 tire will be out of the picture very shortly so far as heavy american cars are concerned. Packard and Cadillac are already on the 7.00-19 tire and Lincoln has been running tests on the 7.00-19 and expect to adopt it in the near future on their drop center rim. Of course, we never know when cars may go back to higher wheels, but this does not look promising for the future. In answer to question 2, we find no tendency to go to drop center rims for 7.00 tires except in the case of Lincoln, where they have been using the rim now for nearly a year. Cadillac have planned some experiments using the present 4.00 standard drop center tire and rim on 18" and 19" diameter wheels, but it is our opinion they are not strongly interested in this rim at the present time for production. Therefore, rim companies in general have not made the 4.00 drop center rim. Firestone have made it and Kelsey-Hayes have made experimental rims, but there is no great interest in this rim outside of Lincoln job. In answer to question 3, we believe that the 19x7 drop center rim in the 4" section would be used if adopted by heavy car manufacturers in this country. In answer to question 4, the bead widths of American made 7.00-20 and 7.00-19 tires is 3/4". The ledge width of the 4.00 rime is .31" or 13/16" to a point slightly over the shoulder. | ||