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).
Customer complaints regarding large tyres on the Bentley 'M' series and recommended tyre pressures.
| Identifier | ExFiles\Box 158\1\ scan0227 | |
| Date | 2nd December 1958 | |
| W/s. (Gx). 1339 c. Mr. [redacted] c. Rm.{William Robotham - Chief Engineer} c. Bly.{B. W. Bleaney - Bentley Sales} BY.11/G.2.12.58. BENTLEY - SECOND HALF OF 'M' SERIES. RE: LARGE TYRES. There are, of course, two possible causes for a customer's complaint :- (a). The weight of the tyre and the rim i.e. of the whole wheel is obviously increased, and the weight increase is at the most critical point, that is on the rim. This must result in rather more reactions upon the car on a road with bad surfaces at high speeds. (b). It is admittedly difficult to considerably improve the ride by increasing tyre dimensions unless at the same time the flexibility of the tyre is increased to take full advantage of the somewhat reduced pressure which one can run at with the larger section tyre, its disability is a function of the stiffness of the wall. On the whole, however, there is felt to be a distinct gain in comfort by the use of the larger tyre. To overcome the difficulty you are meeting in demonstrating the car I would suggest that you run the tyres with the following pressures :- Front 23 lbs. Rear 26 " There is no objection to this other than the question of steering control, and I do not think that we have reached a critical point in tyre in relation to steering re-actions. BY.{R.W. Bailey - Chief Engineer} BM | ||