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).
Visit to Lord Cholmondeley regarding tyre options for his Bentley, discussing comfort, noise, and grip.
| Identifier | ExFiles\Box 89\4\ scan0216 | |
| Date | 23th December 1937 | |
| To Rm.{William Robotham - Chief Engineer} from Rm{William Robotham - Chief Engineer}/IMW.{Ivan M. Waller - Head of Chateauroux} 261(3) 23.12.37 VISIT TO LORD CHOLMONDELEY We delivered two 17" Bentley road wheels from the Experimental Garage Stores, and fitted with new 6.50-17 Standard India tyres (with the noisy tread) to Houghton Hall, Norfolk. We first enquired as to what characteristics his Lordship was seeking in asking for these tyres and also his reasons for wanting them at the rear of the car only. He told us that it was increased comfort that he was looking for and that the combination of large rear tyres and standard front tyres was recommended to him by Sr. We endorsed the fact that this combination would give excellent steering characteristics, possibly better than with the large tyres in front as well. On the other hand we pointed out that more comfort would be obtained with large tyres all round. We informed his Lordship of the short pendulum lever, should he subsequently decide to fit large front tyres. We then discussed the question of the silent tyres which are on order for his Lordship. He pointed out that he is in the habit of having all his tyres sliced by the Tecalemit process; this alone makes any tyre noisy. He therefore said he preferred the tyre with the best grip and enquired as to the relative anti-skid properties of the standard and silent India tyres. We replied that tests we had carried out on the skid-pan showed that ('Silent' 6.50-17 Indias have a better cornering power than the Standard (noisy) 5.50-18 Indias at present standardised, but that the noisy 6.50-17 were superior to the silent treads of the same section. His Lordship would therefore prefer to have the standard 6.50-17 tyres as loaned to him, and would be willing to keep these actual tyres and wheels if he likes them after further test. We think that the alternative of standard tyres could be recommended to owners who are prepared to put up with noise in return for better adhesion having regard to the high road speed of the Bentley. Lord Cholmondeley is of the opinion that the slicing of the tyres increases the cornering power, as well as the grip when braking and suggested that we obtain skid-pan figures to show whether this is so. We ourselves should be interested to do so. | ||