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).
Test report on the accuracy of a speedometer fitted to vehicle 44-PK.
| Identifier | ExFiles\Box 50\4\ Scan077 | |
| Date | 12th March 1925 | |
| Hs. {Lord Ernest Hives - Chair} XL308 Mx {John H Maddocks - Chief Proving Officer} 24/T12.3.25 re Speedometer fitted to 44-PK. A test of this Instrument 12486/720 which I considered was approximately 10% fast on the road, showed as an instrument it is only about 7% i.e. 720 R.P.M. checked by Hasler, it showed 64 M.P.H. This test was taken with the steel back plate in the correct position, allowing for the thickness of the Instrument Board. Mx. {John H Maddocks - Chief Proving Officer} | ||