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).
Performance of 7½ inch tyres on the Phantom III model.
| Identifier | ExFiles\Box 158\1\ scan0156 | |
| Date | 19th November 1937 | |
| W/S. Cx.{Major Len W. Cox - Advertising Manager} from Rm.{William Robotham - Chief Engineer} 1339 Rm{William Robotham - Chief Engineer}9/R.19.11.37. 7½" TYRES ON P.III. Replying to Cx{Major Len W. Cox - Advertising Manager}14/KW14.11.37., we did a number of tests on the Nairobi car on 7½ tyres, and to the best of our recollection the situation on this car was no worse than that of the Bentley when fitted with 6½ tyres. We have, however, no equipment of this size at present in the Experimental Dept., and, therefore, cannot check up on our previous impressions. We should like to do this if there were any chance of these tyres being standardised on the P.III. The main trouble at the moment is that as far as we know there are no silent moulds in existence for this size of tyre. We can confirm that the increase in gear ratio is negligible. Rn.{Mr Robinson} | ||