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).
Effects of using mismatched tyre sizes on the differential and proposing a 10,000-mile test.
| Identifier | ExFiles\Box 81\1\ scan0078 | |
| Date | 1st September 1919 | |
| COPY R.R. 235 B (200 T) (S.L. 64, 22-5-19) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2376 <3044 To BN.{W.O. Bentley / Mr Barrington} from R.{Sir Henry Royce} Copy to CJ. R7/G1/9/19. RE TYRE SIZES FOR PRESENT 40/50 H.P. CHASSIS. With reference to tyres, the views put forward in your memo. (Bn{W.O. Bentley / Mr Barrington}4/W28819) are exactly as I meant them to be. I do not, however, anticipate any trouble in the differential if occasionally 135 m/m was used instead of 150 m/m on the back axle. I do not think anyone would habitually go about with odd tyres, but I think it would be quite wise if the next car that goes on test for 10,000 miles had odd tyres, and the differential was particularly examined at the end of the 10,000 miles. If it was found to be in good order, I would expect that there was no cause for fear on account of the risk of odd tyres being used. R.{Sir Henry Royce} | ||