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).
Dunlop wheels with Goodyear demountable rims, comparing tyre stiffness and weights against a standard wheel.
| Identifier | ExFiles\Box 45\1\ Scan001 | |
| Date | 13th November 1919 | |
| R.R. 135A (100 T) S. G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 643. 19-3-20) G 2618 X 4050 EH2/LG13.11.19. To R.{Sir Henry Royce} from EH. c. to CJ. c. to Bn.{W.O. Bentley / Mr Barrington} c. to E.{Mr Elliott - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} X.3725. X.200. X.4050. RE DUNLOP WHEELS WITH DEMOUNTABLE RIMS. Messrs. Dunlop have submitted to us a pair of straight sided tyres 32 x 4 1/2 mounted on Dunlop wheels which are built up with Goodyer demountable rims. The size of the tyre gives one the impression of the 895 x 135 tyres. The demountable rim works quite effectively. We tried taking the new tyre on and off. The straight sided tyres which are fitted to these wheels are rather stiff in the walls so that it is rather difficult for one man to fix in the position to the spring ring.. The American tyres we have seen are much more pliable than these Dunlop and would make the operation of changing a tyre very much easier. The actual weight of the straight sided tyre and wheel fitted with demountable rim is no more than the standard wheel fitted with 895 x 135 tyre. Below are the particulars of the weights:- | | Standard wheel fitted with 895 x 135 - magnum tyre complete. | Wheel fitted with Goodyear demountable rim - Dunlop straight sided tyre 32 x4 1/2. | | :--- | :--- | :--- | | Wheel. | 38.25 | 41.75 lbs. | | Tyre. | 38.75 with 4 security bolts. | 31.50 lbs. | | Total | 74 lbs. | 73.25 lbs. | | ||