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).
Comparing 14-tooth and 15-tooth axles regarding performance, engine wear, and petrol consumption for tests on 40/50 cars at Brooklands track.
| Identifier | ExFiles\Box 49\1\ Scan185 | |
| Date | 1st July 1922 | |
| BJ. from Hs.{Lord Ernest Hives - Chair} X3545 Hs{Lord Ernest Hives - Chair}1/LG8. 7. 22. TESTS WITH 40/50 CARS ON BROOKLANDS TRACK. X4299 X3545(crossed out) X78F(crossed out) We shall be sending an open car fitted with a 14-tooth axle to Brooklands on Tuesday in order to make a test comparing 14-tooth and 15-tooth axles. It should be borne in mind that the tests on Brooklands will only have a limited value because the speeds on there will be greater than is usually attained on the road. We think the most valuable data is that obtained from the average results of a number of cars. We have now fitted a fair number of 14-tooth axles - the average results show that if the maximum speed of the car is 65 M.P.H. with a 15-tooth, it will be approximately the same with a 14-tooth axle with the advantage of quicker acceler-ation. If the maximum speed of a car is 75 M.P.H. with a 15-tooth axle, then with the 14-tooth axle it will be reduced to approximately 67 M.P.H. The reason why Mr. Royce is not anxious to fit the 14-tooth axle is because of the increase in engine speed causing increased wear and tear and increased stresses. What this amounts to can only be proved after a very consid-erable amount of running. As regards the petrol consumption, we have already carried out comparative tests which show that with the 14-tooth the consumption is 5 to 6% greater than with a 15-tooth axle. Hs.{Lord Ernest Hives - Chair} | ||