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).
Performance comparison table for various car models, detailing engine specs and hill climb results.
| Identifier | ExFiles\Box 125\2\ scan0038 | |
| Date | 1st May 1929 guessed | |
| CAR. | 12-G4. | 12-G4. | 14-G4. | 17-G4. | Chrysler. | 21-EX. Engine. | Std. 20 HP. | .2" on bore. R= 5.25/1 14% larger car. | R= 5/1 Turbulent head. | Std. 20 HP. | '75' | S.S. Capacity C.C. | 3127 | 3558 | 3127 | 3127 | 4079 | 7688 Eng. revs. per mile top gear. | 3069 | 3008 | 3069 | 3021 | 2708 | 2286 Tyres and wheels. | 31 X 6.19" rims. Triple stud tread. | 31 X 6.19" rims. silent tread Fort. | 31 X 6 19" rims. Triple stud trd. | 31 X 6 19" rims. Triple stud Fort. | | 33 X 6.75 Silent tread. Weight. | 33-3-7 | 31-1-7 | 34-0-0 | 34-3-14 | 32-2-21 | 48-1-7 Litres/ton/mile. | 5676 | 6826 | 5645 | 5417 | 6757 | 7256 StantonHill | 10 MPH. | 10 MPH. | 10 MPH. | 10 MPH. | 10 MPH. | 10 MPH. Fin:MPH. | 19 " | 30 " | 18 " | 16 " | 29 " | 29 " Time secs. | 32 | 20.4 | 34.6 | 36.4 | 22.8 | Ticknall Hill, Gate. | 10 " | 10 " | 10 " | 10 " | 10 " | 10 MPH. Fin:MPH. | 26.5 " | 33 " | 29 " | 26 " | 32 " | 31 " Time secs: | 43 " | 47 " | 48 " | 44 " | 55 " | 60 " | 79 | 62 | 71.4 | 80.4 | 64.2 | 58.8 PisternHill. | 10 " | Too fast to drive up this hill. | 10 " | 10 " | | Max: MPH. | 41 " | | 44 1/2 " | 40 " | | Min:MPH. | 17 " | | 23 " | 14 " | | Time secs. | 112.4 | | 100 | 122.0 | | PisternHill. MPH Δ | | 10 MPH. | | | 10 MPH. | 10 MPH. Finish. | | 32 " | | | 29 " | 30 " Time secs. | | 37 " | | | 35 " | 35.5 " | | 60 | | | 68.8 | 63.2 | ||