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).
Comparing the A.T. and Jaeger speedometers, recommending the continued use of the A.T. model.
| Identifier | ExFiles\Box 165\4\ img035 | |
| Date | 11th February 1929 | |
| W/S. (c). c. Hs.{Lord Ernest Hives - Chair} re SPEEDOMETERS. Referring to C10/C7.2.29. in which you put forward the Jaeger speedometer as a replacement for the A.T. speedometer, I have gone carefully into this matter again in view of the points stated in your memo quoted above. In Hs{Lord Ernest Hives - Chair}'s memo Hs{Lord Ernest Hives - Chair}1/LG.23.1.28., whilst he states that these have been running on cars for several months, and have given no trouble, you will appreciate that his expressed opinion is in favour of continuing with the A.T. speedometer. In comparing the two instruments the A.T. speedometer is a precision instrument, very carefully produced, and having a high class finish, whereas the Jaeger is the ordinary type of speedometer supplied on the Small car. The A.T. Speedometer as you are aware depends for its speed registration on electrical phenomena which give a dead beat action to the finger, and incidentally makes it possible to produce an instrument in which the driving flex runs at a low speed, and further it will register accurately at low speeds. In the case of the Jaeger instrument, the speed registration is obtained by a centrifugal governor effect and in order to make this reliable at low speeds the flex of the instrument must be run at a high speed in common with such instruments as the Smith and the Watford, in fact there is no difference at all either in finish or principle between a Smith speedometer and a Jaeger. From a comparison of actual instruments at our Works, I would say without hesitation that the Jaeger looks what it is - a cheap instrument, and that in my opinion it is not suitable as a result of its construction and appearance for use on a Rolls-Royce car. Since we produce the last word in finish on the car, it seems to me to be entirely wrong to try and reduce the amount we spend on the instruments by buying the same type of instrument one would get with a cheap car. The high speed flex will give increased wear and tear and noise. After examining the two instruments I entirely endorse Hs{Lord Ernest Hives - Chair}'s views that we should stick to the A.T.speedometer, which is an instrument which has the Rolls-Royce characteristics, and in addition we have expended a great deal of time | ||