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 Seiberling Rubber Company regarding the development and testing of wide base tires.
| Identifier | ExFiles\Box 156\3\ scan0210 | |
| Date | 16th August 1940 | |
| COPY. SEIBERLING RUBBER COMPANY, AKRON, OHIO. August 16th. 1940. Major R.F. Fuller, J.P., The Avon India Rubber Company, Ltd., Melksham, Wiltshire, England. Attention:- Dr. J.G. Mackay. Dear Sir: This is in reply to your letter of July 18th. regarding wide base tires being developed in this country. Firestone pioneered this development over here and recently made certain proposals to the Tire & Rim Association and the Association agreed to adopt the proposals as a testing program before approving the establishing of experimental practice for these tires. Shortly after the subject was introduced, it was decided to delay the presentation of the program to car manufacturers because of their preoccupation with matters of National Defense. It is not expected that the tires will be used on any 1941 model cars, but undoubtedly the rubber companies will be testing wide base tires during the next year. We have obtained some wheels and expect to do some testing, but the program has not yet been decided upon. Following is the tabulation showing the proposals for the testing program, as adopted by the Tire & Rim Association. This is given as a matter of information and has no official status. Size. Maximum Section Rim Load Inflation. 6-16 6.25 5.00 EW 815 lbs. 26 lbs. 6 1/2-16 6.80 5.50 EW 925 lbs. 26 " 7-16 7.35 6.00 FW 1050 lbs. 26 " 7 1/2-15 7.95 6.50 FW 1095 lbs. 24 " 7 1/2-16 7.95 6.50 FW 1145 lbs. 24 " 8-16 8.55 7.00 GW 1230 lbs. 22 " The advantages claimed by Firestone are improved treadwear primarily, somewhere around 20%, along with somewhat greater stability. For a tire of given inflated width, a wide base tire has a smaller carcass than a conventional tire of the same width; hence, would cost less. The program seems to us a sensible one, and the claimed advantages do not seem unreasonable, though it remains to be seen how much improvement in treadwear can be obtained. Firestone say they have had no carcass or tread cracking difficulties. Their tests were based on tires with 38 degree crown angle, rather than the extremely low angle of 30 degrees used in Pilote tires. When we have further information on this subject, you may be sure we shall pass it along to you. Yours very truly, SEIBERLING RUBBER COMPANY, Manager, Foreign Plant Service. | ||