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).
D.W.S. jacks, wheel sizes, and clearance for wheel changing on cambered roads.
| Identifier | ExFiles\Box 26\3\ Scan232 | |
| Date | 28th July 1933 | |
| To E.{Mr Elliott - Chief Engineer} from Hs{Lord Ernest Hives - Chair}/Lid.{A. J. Lidsey} Hs{Lord Ernest Hives - Chair}/Lid.{A. J. Lidsey}7/KT.28.7.33. D.W.S. JACKS. E.3/HP.28.7.33. This case was brought to our notice some little time ago. The car we believe was fitted with 20" wheels; our present cars (on which jacks are standardised) are fitted with 19" wheels thus giving us 1/2" more clearance for wheel changing. As only one jack is fitted to the front axle it is always possible to reproduce the effect you mention, if one finds a sufficiently well cambered road. When this occurs the nearside front wheel can always be made clear of the road by jacking up the nearside rear wheel. The jack manufacturers are giving us in the near future jacks with increased lift, this will help to minimise this defect. Hs{Lord Ernest Hives - Chair}/Lid.{A. J. Lidsey} | ||