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 results table comparing gearbox performance and settings on various cars.
| Identifier | ExFiles\Box 136\1\ scan0161 | |
| Date | 18th October 1935 | |
| -2- Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls}25/KW.18.10.35. CAR | TEST | RESULT (8) Buick | Original condition. .005 sliding piece, .005 C.M. pitch line, .015 sideshaft and float. | No chunking (9) Buick | (a) Sliding piece increased to .025, and subsequently - (b) C.M. pitch line increased to .012, and subsequently - (c) C.W. instead of Whitmore's oil. | No difference (10) | 9 (c) Except that 3rd motion shaft coupling given .005 rotational and .008 end slack | (11) 30-EX | New RR gears. All gears tight on splines. C.M. .001, 3rd speed overall .004, 2nd speed .002, direct drive .001, all at 1 1/2" radius. | No chunking (but synchro engagement sticky). (12) 30-EX | Early set of gears, large amount of slack of unknown amount, shafts end loaded, loose pinions .001 clearance endways and on diameter. | No improvement (13) 32-EX | As sent to France C.M. .006, Direct drive .0165) 3rd .004, 3rd .020 } 2nd .0035, 2nd .017 } Overall measured at 1 1/2" on 1st motion shaft. | Better than 5 but not good enough standard | ||