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 discussing discrepancies in Dunlop's blueprints for well-base rims and their impact on wheel offset and wobble.
| Identifier | ExFiles\Box 42\1\ Scan052 | |
| Date | 22th April 1926 | |
| Y3609 HS.{Lord Ernest Hives - Chair} BYS/H.{Arthur M. Hanbury - Head Complaints} 22.4.26. WHEELS WITH WELL BASE RIMS. We recently obtained blueprints from the Dunlop Company, of their proposals for the well base rims, medium pressure tyre type. We find that these drawings do not agree with the straight sided wheels, in as much as the distance from the cone of the shell where it locates on the hub, to the centre line of the tyre is greater on both the 40/50 HP. and 20 HP. chassis on the medium pressure type wheels than it was with either the S.S.wheel or fullballoon with well-base rims. In the case of the 40/50. the departure is 1/4" in the direction of increasing the offset from centre point steering. In the case of the 20 HP. the increase of offset is .4375 We can only imagine that the change of management at the Wheel Works has resulted in less care being taken in making changes, as we have not given them any indication that such changes were required or were we expecting them. We have taken the matter up with Wd.{Mr Wood/Mr Whitehead} to get the Dunlop people over and come to some understanding as to exactly how this error has crept in. It certainly has not arisen at this end, and in the past the Dunlop Company have been very careful to send us blueprints of changes they propose to make, even on small details, to obtain our comments on same before making any definite departure. I am writing you particularly at the moment on this matter because I notice that in Mr.Hancock's report on the running of the 20 HP. car, he distinctly states there is no tendency to wheel wobble, but it is quite possible this mistake on the part of the Dunlop Company, which increases the offset by 7/16ths on the 20 HP. car, is in the direction to prevent wheel wobble being set up, and when we go back to correct dimensions we should be misled by the experiments on the wheels, which are being run at the moment, which will have been produced to the incorrect drawings we are now criticising. BY.{R.W. Bailey - Chief Engineer} By | ||