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).
The performance and limitations of a Dunlop jack designed for balloon tyres.
| Identifier | ExFiles\Box 53\2\ Scan151 | |
| Date | 1st December 1924 | |
| 4865 Dec. 1924. DUNLOP JACK FOR BALLOON TYRES. X.4865 X.4124 Lowest position of Jack - HEIGHT. At present. Previously. 5 11/16" 6 3/16" 1st. stage of Jack. 9 9/16" 10 7/16" 2nd. stage " " 11 5/8" 13 1/8". ------------------------- Front (axle) Height from floor. Rear (spring clips). height from floor Taking wheel off - 11 3/4" Taking wheel off - 11 3/4" inflated. Can just inflated. manage to get wheel on and off with full limit of jack (11 5/8") but not O.K. One bare rim 6" Both bare rims. 5 3/8" ------------------------- As above the maximum lift is not enough to allow of taking an inflated tyre off the front - the smallest compass of the jack on the other hand is too high to allow of a bare rim to be taken off the rear (one bare rim already being on the opposite wheel) by 5/16". | ||