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 discussing the development and testing of wide base tyres pioneered by Firestone.
| Identifier | ExFiles\Box 156\3\ scan0208 | |
| Date | 16th August 1940 | |
| COPY. SEIBERLING RUBBER COMPANY. AKRON, OHIO. August. 16th. 1940. Major R.F.Fuller J.P., The Avon India Rubber Co.Ltd., Melksham, Wilts. Attention : Dr. J.G.Mackay. Dear Sir, This is in reply to your letter of July 13th, regarding wide base tyres being developed in this country. Firestone pioneered this development over here and recently made certain proposals to the Tyre and Rim Association and the Asscn. agreed to adopt the proposals as a testing programme before approving the establishing of experimental practice for these tyres. Shortly after the subject was introduced, it was decided to delay the presentation of the programme to car manufacturers because of their preoccupation with matters of National Defence. It is not expected that the tyres will be used on any 1941 model cars, but undoubtedly the rubber companies will be testing wide base tyres during the next year. We have obtained some wheels and expect to do some testing, but the programme has not yet been decided upon. Following is the tabulation showing the proposals for the testing programme, as adopted by the Tyre & Rim Asscn. 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. 6½-16 6.80 5.50 EW 925 lbs. 26 lbs. 7-16 7.35 6.00 FW 1050 lbs. 26 lbs. 7½-15 7.95 6.50 FW 1095 lbs. 24 lbs. 7½-16 7.95 6.50 FW 1145 lbs. 24 lbs. 8-16 8.55 7.00 GW 1230 lbs. 22 lbs. The advantages claimed by Firestone are improved treadwear primarily, somewhere around 20%, along with somewhat greater stability. For a tyre of given inflated width, a wide base tyre has a smaller carcass than a conventional tyre of the same width; hence, would cost less. The programme 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 no carcass or tread cracking difficulties. Their tests were based on tyres with 38 degree crown angle, rather than the extremely low angle of 30 degrees used in Pilote tyres. 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. | ||