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 Pierce-Arrow Motor Car Company regarding wheel rim design, fractures, and associated manufacturing issues.
| Identifier | ExFiles\Box 42\4\ Scan143 | |
| Date | 9th June 1920 | |
| THE PIERCE-ARROW MOTOR CAR COMPANY Elmwood Ave. - Buffalo, N. Y. June the Ninth 1 9 2 0 Rolls-Royce of America, Inc. Springfield, Mass. Attention - Mr. M.{Mr Moon / Mr Moore} Olley, Chief Engineer. Gentlemen:- In answer to yours of the fifth instant, we as you probably know, are equipping our cars with wood wheels as standard equipment. Where our customers specify wire wheels we supply the Rudge-Whitworth Wire Wheel made by the Standard Roller Bearing Company of Philadelphia, Pa.{Mr Paterson} We have accepted the rim that they standardize in conjunction with their wire wheels, this is the Stanweld detachable rim, and as far as the writer knows this rim has given us no trouble. In selecting the rim that we use for our wood wheel equipment we were largely influenced by the design of the rims that are on the market, our choice boiling down to two rims, one the Firestone and the other the Goodyear, these are shown on Figure One and Figure Two of the enclosed sketch. Two or three years ago we had quite a lot of trouble with the rim that we were then using which was very much like Figure Two, having a very sharp corner at the point marked "X". The Maker's full size drawing of this rim indicates a radius of about 1/32" at this point, but in practice this comes out a very sharp corner and frequently starts a fracture that cannot be seen under ordinary inspection. We have had several cases of rims, not of the Goodyear make, in which this part of the rim fractured and the locking ring indicated by "R" was blown off, severely injuring persons standing near. I therefore consider that Figure One is a far better design in regard to this feature; however, on this make of rim, whilst we have had no failures at this point, we have had partial failures on the opposite side at point marked "A" - these have never occurred all the way around the rim, the longest fracture being a foot long. The full size Maker's drawing of this rim indicates about 1/16" radius at this point, in actual practice this frequently is a very sharp corner and the method of manufacturing these is such that this starts a fracture at this point. We have taken these matters up with the Makers of this rim and they claim that they are trying to get the tire makers to permit a larger radius at this point. The interior shape of these rims is controlled by the American Rim Association and no departure can be made from sections without a change in the standards of the Rim Association. | ||