Wheel rim specifications, comparing company standards with Ford's and arguing against certain changes.
| Identifier | ExFiles\Box 158\1\ scan0062 | |
| Date | 21th February 1928 guessed | |
| - 2 - For instance, whilst we would prefer to leave things as they are, we could accept a small reduction in flange height. Then again, on the question of the rim width, we would suggest that it is undesirable to alter the existing standard rim widths, but if a wider rim is required, this could be provided by "sizing up one" - that is to say, it should be permissible to use the 4" section in place of the 3-1/2" section. On this basis, the Ford rim has a width of 2.75" whereas our 4" rim has the standard width 2.688". The Ford flange height is .656" - ours retains the standard 4" flange height of .78" - this is a point on which we could agree to some modification. The well depth is .625" in the Ford rim, but .56" in ours. We certainly would not like to increase our present well depth and if we adopted the shallower flange of the Ford rim, we should certainly prefer to still further reduce the depth of the well rather than increase it. We find our well depth of .56" amply deep enough even with the flange height of .78". We must retain our present 3-1/2" rim. It is the size in biggest demand, and is absolutely satisfactory for the smaller sections 4.40, 4.50, 4.75, and 5.00. As to bead seating widths. This is perhaps the vital point in regard to drop centre rim designs. Granted the possibility of making a sufficiently narrow bead, everything is in favour of using the narrowest bead and the narrow bead seating on the rim. If you widen the bead seat, you narrow the drop centre which is objectionable both from the point of the tube and from facility of fitting the cover. The wider bead in itself increases the difficulty of handling in mounting and dismounting, and in addition, the wider bead in the narrower drop centre still further increases the difficulty of handling. Whilst we could agree some very minor modifications of bear seating widths, we think it entirely unnecessary, for we have no difficulty in making beads as per the sample section supplied, and bead trouble is a thing entirely unknown to us on these drop centre rims. One further point, and that is in relation to the position of the valve hole. Fitting the valve as we do at the side, is a convenience in every way, and is much appreciated by users. It also provides an economy in the valve, and cuts out all different valve lengths - a point which is very specially appreciated by dealers. If you think that this matter could be brought definitely to a head shortly, and that it would assist matters if we could send someone over, I feel sure we could arrange for perhaps Mr. Fellowes to pay a flying visit to deal with any points that might be raised on our experience with this type of equipment. (Continued) | ||
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).