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).
Inconclusive road tests comparing the springing and ride comfort of two different chassis models.
| Identifier | ExFiles\Box 69\2\ scan0120 | |
| Date | 22th July 1924 | |
| X8770 To OJ. from BJ. Copies to H.{Arthur M. Hanbury - Head Complaints} Hs.{Lord Ernest Hives - Chair} BJ5/H22.7.24. On the evening of the 21st, PN.{Mr Northey}, OWB., Hs.{Lord Ernest Hives - Chair} and BJ. made the following tests at Gerrards Cross. 107-MG (a short chassis) was taken as a sample, in its ordinary state in which we give demonstration runs to customers. 98-NK (a long chassis) was fitted with springs 12% stronger than the 40/50 h.p. standard springs, front wheel brakes and heavy axle. The front wheel springs, however, were only "rated" as above, but they were neither of the same principle of construction as our present standard (or 107-MG), nor were they on the same principle as the springs which will be delivered on all the cars fitted with front wheel brakes. For instance, the springs on 98-NK, which were rated 12% stronger than 107-MG, had a depth in the centre equal to one and a half diameters of a penny, whereas the depth in the centre of the springs on 107-MG was equal to two and a half diameters of a penny. There were seven leaves in the springs on 98-NK, and fourteen leaves in the springs of 107-MG. It was realised that whatever the "rating" of a spring might be, yet an alteration in the construction of it might give a different result in regard to comfort, swaying, pitching and other points. For this reason the above tests were inconclusive. The impression formed of 98-NK in the above tests was that the springing was not quite as good as 107-MG, but so far as users of open touring cars are concerned, (who are not so particular as users of closed cars), they were not likely to object to the springing, more especially as the springing can be considerably altered to accommodate each customer, by adjusting the back shock-absorbers. The main discomfort experienced was an increased feeling of solidity in the bumping over pot-holes or unevennesses, which was possibly caused by the extra unsprung weight on the front axle, more than by the increased strength of the spring. On the other hand, from experience in other tests, it had been found that a 25% stronger spring increased these | ||