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 to Dunlop Rubber Co. Ltd. discussing a new 32 X 6 tyre being standardized in the US market and suggesting testing.
| Identifier | ExFiles\Box 53\2\ Scan003 | |
| Date | 21th November 1922 | |
| X4585 Hsl/LG. 21st. Nov. 1922. Messrs. The Dunlop Rubber Co.Ltd., Aston Cross, Birmingham. Dear Sirs, For the attention of Mr. Paull. We have recently received information from our American Factory, that the American Wheel and Tyre manufacturers are producing a 32 X 6 tyre in place of the 33 X 5. The following is an extract from their letter :- "There is a movement on foot here to standardise a 20" wheel instead of a 23" wheel. The wire wheel and tyre makers are all for it and are already making them. The tyres will be 28 X 4 (Ford, etc.), 29 X 4½ (covered Ford, Overland etc.), 30 X 5 (Hup, Buick 4, etc.) 32 X 6 (Rolls-Royce, etc. 34 X 7 (fast trucks, etc.). We are getting a set of 32 X 6 for Belnap, and a set of 30 X 5 for my Hup. The actual size of a 32 X 6 as regards rolling diameter is about the same as a 33 X 5; tyre pressure is 40 lbs. instead of 65 lbs. The advantage claimed is, roughly, to get a greater life than the present cords, with the riding qualities of the old canvas tyres. The rolling resistance is said to be scarcely increased (not so great as the old canvas tyres anyway). Also, freedom from punctures, no breakage of side walls, and a cushioning effect on the wheels when they are stressed by side-skids (due to rolling-over of the tyre). Finally, the big gain is said to be increased traction coefficient and virtual elimination of brake jaggers in the rear axle, and consequently, they hope, the defeat of the 4-wheel brake movement in the U.S., which apparently frightens the tyre makers. I thinks you should test several sets of 32 X 6 tyres and wheels, before you take the plunge on 4-wheel brakes. Will you consider this? We should be glad to send you a set or two if you think it desirable. Contd:- (upside down text) K.R. 199 (250) (DS878-19-7-21) MPIBOGAS | ||