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).
Comparison of the performance of 14-tooth and 15-tooth axles in different car configurations.
| Identifier | ExFiles\Box 49\1\ Scan342 | |
| Date | 2nd July 1921 | |
| COPY. BJ. PN{Mr Northey}1/DN2.7.21. COMPARISON OF 14 AND 15-TOOTH AXLES. On the 28th.inst. I drove 81-TW to Derby by arrangement in order that comparative tests could be made by Hs.{Lord Ernest Hives - Chair} and myself between 1.EX fitted with the 14-tooth axle and a standard open trials car fitted with the 15-tooth axle. We tried the cars up hills which are well known to Hs.{Lord Ernest Hives - Chair} I was very much pleased with the performance of the 14-tooth pinion and have formed the opinion from the tests we then made that axles having the 14-tooth pinion, would be altogether satisfactory for closed types of cars, but only suitable for those types of open car in which we had reason to be satisfied that the owner thought less of high speed than of high average speed. The acceleration and hill-climbing powers of the 14-tooth axle were, however, remarkably good, but with the car in question the limit of speed appeared to be reached - (both bodies were of the open type) - at 65 miles an hour on the level under the best conditions. I think that the 15-tooth axle is best all round for open touring cars. I was not able to detect any unpleasant engine vibration or fuss with the 14-tooth axle, even at higher speeds and there is undoubtedly less engine vibration when picking up. I hope that as soon as possible the 14-tooth axle will become standard for all chassis on which it is intended to fit closed bodies. P.N. sgd. | ||