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).
Recommendation on speedometer standards for S.S. and 20 HP models to ensure accurate readings with different rim sizes.
| Identifier | ExFiles\Box 50\4\ Scan303 | |
| Date | 4th July 1929 | |
| [illegible strikethrough] xH308. To Bv. from Hs {Lord Ernest Hives - Chair} /Rn. {Mr Robinson} Hs {Lord Ernest Hives - Chair} /Rn {Mr Robinson} /J1.4.7.299 Copy to Mx. {John H Maddocks - Chief Proving Officer} EFC. {E. Fowler Clarke - Electrical Engineer} x 7310 x 5310 S.S. and India IV Speedometers. In view of the fact that S.S. owners may fit 20" rims with the smaller tyres to their cars, and 20 HP. owners 19" rims. We recommend that the S.S. Speedometer standard should be 775 cable revs. per mile and the 20 HP xxxxx 720 cable revs. per mile. This will ensure that the speedometers do not read slow under any conditions. Hs {Lord Ernest Hives - Chair} /Rn. {Mr Robinson} | ||