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).
Experiments and proposed solutions for wheel disc design issues.
| Identifier | ExFiles\Box 160\1\ scan0045 | |
| Date | 9th November 1938 | |
| 1001 φ 1260 To By.{R.W. Bailey - Chief Engineer} from Rm{William Robotham - Chief Engineer}/Ory. c. Hs.{Lord Ernest Hives - Chair} c. Da.{Bernard Day - Chassis Design} c. Da{Bernard Day - Chassis Design}/Ev.{Ivan Evernden - coachwork} c. Da{Bernard Day - Chassis Design}/Hdy.{William Hardy} Rm{William Robotham - Chief Engineer}/Ory.3/MH.{M. Huckerby}9.11.38. WHEEL DISCS. We have been experimenting to obtain satisfactory cheap wheel discs. The retail price of a set of Cornercroft "Ace" discs is about £19. We considered the brake drum a sufficiently good seal on the inside, and have therefore experimented with outer discs only. We decided to secure the disc by the wheel nut, the whole disc acting as a large Belleville washer under about 1/10 compression. A set of discs was fitted to Hs{Lord Ernest Hives - Chair}'s car, held to the spokes by two clips to keep them in position when wheel-changing; tyre inflation being arranged by the usual Schrader extension appearing near the centre of the disc. All the discs tended to creep forwards, slip occurring at the edge and against the wheel nut. The nut itself never became loose. Rm.{William Robotham - Chief Engineer} then suggested a layer of rubber between the disc and the wheel rim. This has prevented all creep. .030 rubber bonded to the disc is satisfactory. British Goodrich at Burton can fix the rubber to an already chromium plated disc. We want to get away from the Schrader tyre valve extension. It costs too much and also necessitates the spoke clips which otherwise could be dispensed with. It is easy to hold the disc in position with one hand while tightening the wheel nut with the other. We have, therefore, asked Dunlops whether they can bring out the rubber valve parallel with the wheel axis as it would then only necessitate a small slot in the edge of the disc. This feature looks quite sightly on the 1939 Cadillacs. | ||