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).
Proposing new gear ratios for a sports car to improve performance.
| Identifier | ExFiles\Box 66\4\ scan0239 | |
| Date | 22th September 1927 | |
| S/W. Hs.{Lord Ernest Hives - Chair} Copy to:- BJ. Sg.{Arthur F. Sidgreaves - MD} SECRET Y8310 CWB8/GM/22-9-27. SPORTS CAR. I have been considering the question of the gear ratios of this car and it would seem, that to obtain the very best performance, a modification to our existing gear ratios is desirable, as all the present gears are too low to be of the greatest practical use with a car of this description. I have tabulated below the present gear ratios of our New PhantomCodename for PHANTOM I and the ratios which are considered would be preferable for a car of this description. Gear Ratio. Relative Speed or Torque. New PhantomCodename for PHANTOM I 1. 1. .67 1.48 .45 2.2 .295 3.4 Proposed ratios 1. 1. .76 1.31 .56 1.8 .33 3.0 Assuming ultimate revolutions of 3,000 and a 17 tooth axle, we should have a maximum speed on top gear of 95 m.p.h. which with present New PhantomCodename for PHANTOM I ratios would give 63.5, 42.5 and 28 on 3rd, 2nd and 1st, whereas the proposed ratios give 72, 53 and 31.5 on these ratios. I am not putting forward this suggestion to add to the already very considerable list of alterations which must be made before this car can go on its 10,000 mile test, but for your consideration for further future development of the car. CWB. CWB | ||