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).
Comparison of 3-speed and 4-speed gearbox designs, their ratios, and their suitability for American drivers.
| Identifier | ExFiles\Box 156\4\ scan0030 | |
| Date | 15th January 1929 guessed | |
| - 3 - The Franklin has a three speed box with conventional shift. [Diagram of a 3-speed H-pattern gearbox: Top row: R, 2 Bottom row: 1, 3] The most reasonable arrangement of a four speed box for American users appears to be the new Stutz: [Diagram of a 4-speed H-pattern gearbox: Top-left (separate gate): "EMERGENCY! Low" Top row: R, 3 Bottom row: 2, 4] This is practically the conventional 3-speed shift with an additional "emergency low gear" out to the left. This low gear is locked by the trigger on the change-speed lever. This is undoubtedly best for American users with the conventional central lever without visible gate, since it has the conventional H shaped shift which is in everyone's mind. 3 SPEEDS. We believe that three speeds of our present ratios 1, .67, .355 are ample for our cars, as we have never (in four years) encountered any demand for a lower gear. Only the high and second are used in ordinary handling, and if first is used, one only disengages it with the car in motion, so that with the internal-geared box there would be no engagement of sliding gears at speed. With the four speed internal-geared box there is a possible clash-engagement from first to second. 4 SPEEDS. With a lower gear which really will be used by the unskilled driver, it may be considered however that to work out a three speed box is rather a short-sighted policy, since the obvious tendency will be to go back to an axle-rationof 3.25 (16/52) or even higher. This is especially true on our cars because of the resulting increased smoothness of operation with the higher gear. -continued- | ||