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).
Different Bentley axle ratios and their suitability for various car types.
| Identifier | ExFiles\Box 84\4\ scan0007 | |
| Date | 17th June 1933 | |
| X202 To By.{R.W. Bailey - Chief Engineer} from Hs{Lord Ernest Hives - Chair}/am. c. to Da.{Bernard Day - Chassis Design} Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}3/KT.17.6.33. BENTLEY AXLE RATIOS. All our running in France was done on a 11/43 axle. The two axles we have available in the strengthened gear are the 10/41 and 11/41. We have standardised the 10/41 for the ordinary Bentley, but now that we have run the 11/41 we find that it is altogether too high for anything except a freak car. We shall undoubtedly make some cars the major objective which will be maximum speed and for these the 11/41 axle can be used. We estimate that they will be at a maximum of 5% of the total. We shall need this ratio for the 100 M.P.H. car demanded by Sales. It does appear that the 11/43 is the correct gear ratio for a high geared axle on the Bentley. Unfortunately, however, the test in France on this gear was marred by the failure of the differential, bits of which got in the crown wheel and pinion. Until this happened, we have no evidence that the axle was not O.K. We understand that the stresses in the 11/43 are actually lower than the 10/41. If Da.{Bernard Day - Chassis Design} will confirm this fact, we shall be in a position to recommend this ratio as the standard high geared axle for Bensport. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||