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).
Performance and suitability of Dunlop Modified Silent Tread tyres for different road conditions.
| Identifier | ExFiles\Box 29\4\ Scan074 | |
| Date | 4th March 1931 | |
| To C. From Hs{Lord Ernest Hives - Chair}/RM.{William Robotham - Chief Engineer} x4462 c. to PN.{Mr Northey} Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}4/KT.4.3.31. DUNLOP MODIFIED SILENT TREAD TYRES. Y4050. x4462. C1/C26.2.31. The present position as we understand it is this - For English main road conditions, we recommend the new modi-fied silent tread tyre, i.e. with the additional transverse grooves. Under these conditions the difference in resistance to skidding between these tyres and the triple stud is, as far as we can ascertain from elaborate tests specially carried out by Dunlops, not more than 5%. This is confirmed by road tests. At present we know of no tyre that will reduce this gap of 5% without increased noise. We understand from Dunlops that you considered that customers would not like the appearance of the modified silent tread, hence we sent you the Canadian Dunlop which we consider reasonably silent. If the look of this tyre appeals to you, it might be worth while making some tests on skidding on similar treads, but you must appreciate that there are some hundreds of road surfaces in England each of which has a number of characteristics according to its degree of humidity, and therefore to assess the exact skidding characteristics of a tyre is one of the most difficult propositions imaginable, in fact the only satisfactory opinion is the average of numbers of customers. We should never recommend silent tread tyres for cars to be used exclusively on the Continent or under colonial conditions. Speeds are too high in the first case, and in the second unmetalled roads smother all tyre noise and necessitate the best gripping tread obtainable since on such surfaces the difference between silent and triple stud treads is perhaps 100%. The tread of the India tyres run on the last 10,000 miles test seems to us a reasonable compromise, and we should like the opinions of customers who try it. We do not expect to be able to find a tyre tread that will be capable of covering all requirements to the best possible advantage, any more than we can spring a car to a fixed specification for any part of the world. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||