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).
Dynamometer test results for a Waltham speedometer fitted to a 49-GB car with a 15/52 axle.
| Identifier | ExFiles\Box 36\1\ scan 084 | |
| Date | 20th October 1922 | |
| Mr. Hives from GWH.{George W. Hancock - Head Chateauroux} X2915 20.10.22. WALTHAM SPEEDOMETER FITTED TO 49-GB CAR. 15/52 Axle. Checked over on dynamometer. Correct M.P.H. | Engine revs. | Speedometer. 10 | 355.6 | 7 20 | 711.3 | 17.5 30 | 1067. | 30 40 | 1422.6 | 47 50 | 1778.3 | 63 60 | 2134 | 73 70 | 2487 | 80 33 X 5 Dunlop tyres. | ||