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).
Findings from extensive road tests of Michelin disc wheels, including objections and confirmations.
| Identifier | ExFiles\Box 106\4\ scan0004 | |
| Date | 15th November 1921 | |
| X3599 HS{Lord Ernest Hives - Chair}6/LG15.11.21. /X3599 XZ458a CJ. from Hs.{Lord Ernest Hives - Chair} MICHELIN DISC WHEELS. We have run Michelin Disc Wheels on experimental cars for a total of 28,000 miles. This includes 10,000 miles on 2.EX Car in France in 1919/20. The objections we have proved against Michelin wheels are as follows:- 1. Because of them being disc wheels, a strong cross-wind affects the steering of the car. 2. They are difficult to take on and off. It is practically impossible to do it without getting covered with dirt. We have not been able to confirm any of the points raised in the attached note ref. CJ34/E19.10.21. 1. Lack of resilience. We cannot believe that there is anything in this. One would imagine that the slightest difference in the tyre pressure would swamp any conceivable difference in the wheel. 2. Multiplication of noises. We have not been able to prove this. We have tried changing the wheels from disc to wire a number of times. Sometimes one imagined it made a difference but on the average results the difference could not be appreciated. We however, do not feel absolutely convinced that in some cases they may not increase the tendency for noise. We think it is reasonable to suppose that they may, but we have not been able to prove this. 3. Road shocks imparted immediately to other parts of the chassis. The disc wheels are about 5% heavier than the wire wheels. This is a disadvantage but one could hardly imagine it would be appreciated by passengers. 4. Inclination to buckle. We have tested the wheels for 100 hours on the Bump Test and on there there was no inclination to buckle. We have however, received wheels from the Michelin people which were not running true. We have fitted about 50 sets of Michelin disc wheels for private owned Rolls-Royce cars. So far we have had no cases in England of customers being contd:- | ||