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).
Acceleration performance data comparing two different tyre sizes.
| Identifier | ExFiles\Box 108\1\ scan0382 | |
| Date | 22th February 1938 guessed | |
| ( 2 ) The acceleration figures gave practically the same performance with either tyres. We found this rather difficult to believe, so independent figures were taken by two other Testers who brought in similar results. We therefore give the times in full for your consideration. A) WITH 7.50 x 17" TYRES. Acceleration from 10 m.p.h. top gear. Speedo Reading. Corrected. Times in Seconds. 1st Test. 2nd Test. 30 30 9.4 10.0 9.8 9.2 40 40.2 13.8 15.2 14.6 14.4 50 50.6 21.4 22.2 20.8 20.8 60 60.8 29.8 31.4 28.6 28.6 70 71. 43. 47. 41.4 41.8 Time for Kilometer rolling) 46.8 secs. 45.9 secs. start 10 m.p.h. top gear ) B) WITH 6.50 x 17" TYRES. Acceleration from 10 m.p.h. top gear. Speedo Reading. Corrected Times in Seconds. 1st Test 2nd Test. 30 28.2 8.4 9.4 9.2 9.0 40 38. 12.2 14.2 13.8 13.6 50 47.6 19.4 20.2 18.4 19.0 60 57.1 26. 27. 25.4 25.6 70 67. 35.4 37. 36.2 35.8 Time for Kilometer rolling) 46.8 Secs. 45.0 Secs. start 10 m.p.h. top gear Rm{William Robotham - Chief Engineer}/IMW.{Ivan M. Waller - Head of Chateauroux} | ||