Test report comparing the effects of different tyre types and pressures on vehicle handling and ride quality.
| Identifier | ExFiles\Box 11\2\ 02-page244 | |
| Date | 6th May 1929 | |
| To Hs {Lord Ernest Hives - Chair} /and Rm {William Robotham - Chief Engineer} x794 Hotel de France Chateauroux(French test region) Indre 6/5/29 92 We have today tried the front shock dampers with 100 lbs L and 100 lbs HP without dynamic restrictions. The results are better at speeds over 40 M.P.H. there are less joggles; the periods are of shorter duration. This loading gives approximatly the same results at speeds above 40 M.P.H as we get with 60 lbs L and 60 LBS HP with dynamic restrictions, below this speed the car shudders and generally rides hard. We have still not obtained a steering that for selectiveness we should call OK. It is very elusive, one day it seems OK and the next not at all the selective and with a side wind it is impossible to keep a straight course. We have also triad the steering with the following tyre pressures 50,40;30;20 lbs sq inch Conditions as our report. 50LBS SILENT TREAD TYRES STEERING NOT SELECTIVE JOGGLES AS REPORTED RIDING OF CAR AT SPEEDS UP TO 40 M.P.H. HARD TRIPLE STUD TYRES STEERING NOT SO SELECTIVE BY 5% JOGGLES INCREASED BY 5% RIDING OF CAR AT SPEEDS UP TO 40 M.P.H. HARSHNESS DECREASED BY 10% 40 LBS SILENT TREAD TYRES STEERING SELECTIVENESS NOT ALTERED JOGGLES INCREASED BY 2% JELLYING MORE NOTICABLE RIDING NOT ALTERED 40 LBS TRIPLE STUD TYRES STEERING SELECTIVENESS APPROXIMATLY THE SAME JOGGLES INCREASED BY 10% JELLYING MORE NOTICEABLE RIDING NOT ALTERED 30 LBS SILENT TREAD TYRES SELECTIVENESS OF STEERING A CONSIDERABLY IMPROVED ALMOST OK JOGGLES INCREASED BY 30% BAD PERIOD AT 45 - 48 M.P.H. JELLYING STILL MORE NOTICABLE RIDING OF CAR AT SPEEDS UP TO 40 M.P.H. CONSIDERABLY IMPROVED 30 LBS TRIPLE STUD TYRES APPROXIMATELY THE SAME AS SILENT TREAD JOGGLES INCREASED BY 32% BAD PERIOD 40-58 MPH ALMOST A WOBBLE JELLYING APPROXIMATLY THE SAME SAME AS SILENT TREAD 20 LBS SILENT TREAD TYRES STEERING VERY GOOD FOR SELECTIVNESS 20 LBS TRIPLE TREAD TYRES STEERING VERY GOOD FOR SELECTIVNESS | ||
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).