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 12/50 and 11/50 axle ratios through hill climb and general road performance tests.
| Identifier | WestWitteringFiles\U\January1930-April1930\ Scan087 | |
| Date | 1st February 1930 | |
| -2- dry roads and no appreciable wind. The tests were carried out on these hills side by side. TICKNALL HILL. 12/50 axle. Time for hill - 57.5 secs. 11/50 axle. " " - 63 secs. This does not appear to be a very big difference but represents a difference of 125 to 150 yards between the two cars at the end of the test. The improved low speed acceleration of the 11/50 car is very marked. PLATTS HILL. This is essentially a low speed test and demonstrates the greatest difference noticeable between the two cars. 12/50 axle Time for hill - 95 secs.( The car will only just climb on top gear). 11/50 axle Time for hill - 69 secs. GENERAL. When the two cars are driven over ordinary roads, one behind the other, it is very noticeable that the 11/50 car leaves the 12/50 every time during acceleration etc. It is very seldom that the high speed superiority of the 12/50 ratio is useful under English road conditions. Our opinion is that the 11/50 axle ratio should remain as standard for the high compression - 25 HP. car, and the 12/50 be listed as an alternative for very light sports bodies or for Continental use. It would be fatal to use the 12/50 ratio on heavy bodied town carriages. The presence of the engine is certainly felt more. | ||