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).
Abridged report on the testing of 'India' tyres on a 25 HP car.
| Identifier | ExFiles\Box 29\4\ Scan076 | |
| Date | 17th March 1931 | |
| x+462. To C. From Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}1/MJ.17.3.31. "INDIA" TYRES. We have received the attached letter from Capt. Bowman of the Car Mart. We do not know whether for any reason you do not consider it policy to give a report on a job of this nature, but since these tyres have done so well and Capt. Bowman has on several occasions been very useful to us in obtaining information, perhaps you would like to pass on to him the following abridged report :- Tests have been carried out on a 25 HP. car fitted with 6" x 19" Super Duty India Tyres for 4 1/2" x 19" wheel. These tyres are essentially of the plain ribbed type and are of the pattern indicated in the attached sketch. The following features were noted during tests :- (1) Life. The tyres were run over 10,000 miles at high speeds on the Continent and in the course of the tests careful note was taken of the rate of wear, which was found to be as good as any tyre that we have previously tested. (2) Riding Comfort. It was found that when these tyres were run at 5 lbs/sq.in. below the normal inflation pressure recommended by Dunlops, they gave equally good riding comfort. The tyres were run at this pressure during their test for life i.e. 30 lbs/sq.in. (3) Silence. We are satisfied with the degree of silence obtained on these tyres. (4) Non-skidding Properties. The road adhesion of these tyres is naturally not so good as that of the more elaborate tread patterns but considering the degree of silence obtained we think that they are a very excellent compromise in this respect. (5) Effect of Steering. The steering of the car was not affected adversely by these tyres. It should be noted, however, that the 25 HP. car is far less sensitive to any alteration to tyres, than a 40/50 HP. car and it should not therefore be assumed that because India tyres have passed our tests on the smaller car they will therefore necessarily prove satisfactory on the Phantom II. There is no loss of steering lock with these tyres on the 25 HP. car. Copy of G.P.D. attached to C.s Copy. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||