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).
Outlining the weight increase effects of a new inner tube and discussing the trade-off between added weight and potential advantages.
| Identifier | ExFiles\Box 53\2\ Scan009 | |
| Date | 3rd February 1923 | |
| X4565 To C.J. from Hs.{Lord Ernest Hives - Chair} Hs{Lord Ernest Hives - Chair}2/LG3.2.23. X4565 X20 Referring to your memo. CJ2/E2.2.23. The effect of the increase in weight of the propose new inner tube will be as follows :- % increase in weight. Complete car . . . . . . . . . .7 of 1% Wheel and tyre. . . . . . . . . . 8% Rear axle unsprung . . . . . . . 2.2% weight. Front axle unsprung . . . . . . . 3.5% weight. Addition K.E.of . . . . . . . . complete car at 60 . . . . . . . 1/4 of 1% m.p.h. With regard to the technical objections. These would depend upon what advantages were gained by using these inner tubes. If the advantages were half as much as the claims made by the makers, we should say they would be worth the additional weight. On the post-war cars we fitted larger diameter and heavier tyres because the advantage in mileage and being able to run at lower pressures, more than compensated for the additional weight. We have recently adopted the demountable straight side rim which is slightly heavier. In this case again, it was considered the advantages more than compensated for the disadvantages of the extra weight. Hs.{Lord Ernest Hives - Chair} | ||