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).
Testing modified Dunlop Silent Tread Tyres for road adhesion and noise.
| Identifier | WestWitteringFiles\U\August1930-November1930\ Scan111 | |
| Date | 7th October 1930 | |
| To R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/AJL c.c. to Sy. Wor.{Arthur Wormald - General Works Manager} c.c. to C. Da.{Bernard Day - Chassis Design} c.c. to By.{R.W. Bailey - Chief Engineer} ORIGINAL x4050. x7820 x5820 DUNLOP SILENT TREAD TYRES. We have received for test a set of Dunlop 7" x 20" Silent Tread Tyres which have been modified to improve road adhesion qualities. The standard Silent Tread type is worse for skidding when compared with the Triple Stud tread type which it superseded. The modification to the tread consists of breaking up the three continuous ribs of the tread by cutting transverse grooves in them. The centre rib is grooved at intervals of approximately 1.5" and the two outer ribs at intervals of 3". The width of the groove is .250". The tyres have been tested here from the point of view of noise or any other objectionable feature that may have been caused by the alteration to the tread pattern. The modification, however, has not appreciably altered the silence characteristic of the tyre. A very slight sing is apparent at medium and high speeds but it is not sufficiently prominent to warrant complaint, it is only after changing quickly from one type of tyre to the other that the difference is appreciated. At slow speeds, either on tram line sets or on a smooth road no objectionable increase in noise or vibration is apparent. We are not in a position to state how much the | ||